I'll be honest, I hate talking about super popular Pokemon like these guys because I feel there's a ton of expectations about what I'll say about them---hope this lives up to them. Also, I'm having trouble typing tonight for some reason so forgive any typos.
#092 - Gastly
Ghost/Poison
It's time for the final member of the classic Link Evolution quartet, and probably the rarest, as he was the only one who didn't make the cut into Ruby and Sapphire---Gastly! He's also our first Ghost Pokemon, and part of the only Ghost family in all of Generation I. Ghost was originally quite a strange Type---offensively it was pretty pointless in Generation I, with only two Ghost-type attacks, Lick and Night Shade, and the latter was a fixed damage move, and sources like the show seem to suggest at one point it'd be good against Psychic-types, but they actually are immune to them. So, ultimately, the only point of Lick really is if you're up against another Ghost-type Pokemon, and given that there are only three, that probably won't happen too much. If Gastly was a pure-Ghost Pokemon in Generation I, it would've been quite broken, as not only would it have been able to resist the large amount of Normal-type moves that made up a lot of Pokemon's movesets, it also would've had no weaknesses except the aforementioned Lick. Perhaps as a way to balance this, Gastly was made part-Poison, and thus had to worry about the ever prevalent Psychic Pokemon ruining their fun. We later got pure-Ghost Pokemon, but by then Ghost had gained an additional weakness in Dark, and the common "Bite" changed from Normal to Dark, so they were less broken at that point.
Gastly's Poison-type is interesting, because it and its evolutions have never been able to naturally learn a Poison-type attack throughout the entire series---only through TMs and similar methods, although in Generation I, that was limited to Toxic which almost every Pokemon could learn. They really don't feel like Poison-types that much, and my theory is that in-universe, they were merely given the Poison-typing simply because there was no better way to classify the otherworld gas they're made up of. I wonder who exactly is responsible for deciding what Type Pokemon are---do they rigorously test out every Type match-up in a laboratory somewhere? Is there a code within a Pokemon's DNA that scientists can simply look up to tell? It's a mystery honestly, and why Type match-ups have changed over time doesn't make much sense either, but hey, it's a game. Part of me wonders at what point "Ghost" was decided on as a Type during development, it feels like it was probably one of the last Types included and perhaps at one point the Ghost-type Pokemon were simply just Poison-type Pokemon representing a different type of Poison like the difference between Bulbasaur and Grimer, or maybe they were even Psychic-types since they learn quite a bit of Psychic-type moves, and ghosts could be seen as another representation of extrasensory abilities. Whatever the backstory is, I think most fans are glad that the Ghost-type was created since it's the one Type I feel basically everyone likes.
Gastly's an extremely simple Pokemon, but that's part of the charm---just a smiling black ball surrounded by creepy gas, and nothing more. It's not exactly how most people usually picture a ghost, for many Westerners they probably think of the classic "sheet ghost" (which we've yet to get), but I think most players looked at the design and immediately see it as the otherworldly creature it's meant to be. The PokeDex says Gastly is made up of 95% gas---I imagine the 5% are the eyes---and the original sprites used in both the Japanese Red and Green and our Red and Blue represented this far better, with Gastly basically being a mass of pixels with eyes. However, I imagine using that design for later games (imagine that in the show or in the 3D games) wouldn't look quite right, so all future games went with the classic black-sphere body like the Sugimori Art. Gastly's body being all poisonous gas has its pros, as it can use it offensively to take down even an Indian Elephant, but a major flaw as well, as Gastly is extremely susceptible to the wind and thus must seek shelter whenever it picks up. Personally I like how they gave such a dark Pokemon a flaw like this since it helps "humanize" it a bit, and makes it somewhat cute and something you can imagine yourself capturing and befriending.
So, Gastly have appeared frequently throughout the show as the OG (original ghost), but of course everyone remembers the awesome one that popped up in "The Ghost of Maiden's Peak", capable of speech and a host of other crazy powers. Since just a few episodes later we got a Gastly who had none of these powers and was more or less a normal Pokemon, I always assumed that wasn't a Gastly at all, but an actual "ghost" who merely took a form humans would be familiar with. Anyway, that episode introduced two things---it's the first time I learned what a "mongoose" was (who later was made into a Pokemon), and it made everyone realize how awesome fusion is, since this aired quite awhile before the Fusion Arc of DBZ hit Toonami and Digimon did it. Don't lie, you secretly want Pokemon Fusions to actually happen, every fan knows in their heart that that would be amazing. Well, at least the show is following up on that childhood fantasy---but in a way none of us expected.
#093 - Haunter
Ghost/Poison
Haunter is the evolved form of Gastly, and personally I consider it THE Ghost-type Pokemon. Actually, in Japan, Haunter is literally named "Ghost"---it and the Type share the exact same name. Like the other Link Evolution middle forms, I like it better than the final form, and since not all players will be able to easily evolve it, Game Freak made it decent enough to stand on its own during the main adventure even if you're unable to power it up through trading. Likewise, despite, well, missing much of its body, I feel its design is pretty complete feeling and I would've accepted it as a two-stager.
So, Haunter evolves quite a bit from Gastly, having a much more "solid" appearance that's fleshed out with the addition of a true head, floating arms, and a ghostly tail. The popular theory is that Haunter isn't actually missing its body, but as the PokeDex implies, it's a creature that has somehow ripped a hole into our dimension, but wasn't able to materialize the rest of its body and legs. The classic Red and Blue sprite is often held up as support for this claim, as Haunter certainly looks like he's popping right out from the very fabric of space-time. Most of the Ghost Pokemon appear to be similar to Haunter, unexplainable creatures from possibly another dimension as opposed to the spirits of the dead, who are always treated as being completely different and "spookier" than Ghost Pokemon in the various mediums, especially in the show. Of course, a few recent Pokemon have muddled up this important divide---but then perhaps it is merely the PokeDex attributing superstitious origins to them due to a lack of concrete facts to explain their otherworldly nature.
As far as Pokemon go, Haunter is pretty vicious. It's said to lie in wait for unsuspecting victims so that it can steal their life force---I imagine it doesn't even need to do this to "survive", rather it just enjoys causing pain and suffering. To do this, Haunter licks its victim, causing them to endlessly shudder until they drop dead and die. Whoa. "Licking" is another example of the cultural differences between Western and Eastern ghosts, because as a kid I never heard of ghost licking folks to death, and Lick being a Ghost-type move always confused me---Western ghosts usually tend to just breathe down the hauntee's neck, or throw a bunch of shit around the house. I'm unable to find an exact explanation as to why ghosts licking stuff is so popular in Japanese media, there's a ton of Yokai for example known for their long tongues and licking shit (literally), but it's definitely a thing over there, and like all things Japan, there's probably some pretty kinky fetish art dedicated to it. Uh, not that I looked into that of course.
I actually forgot how dark Haunter really was, because for me the first thing I think of when I think of Haunter is its appearance in the show, where it and the rest of the Ghost-type Pokemon were "neutered" quite a bit and made into misunderstood, mischievous creatures who really didn't mean any harm. Haunter is one of the most debated Pokemon among anime fans due to its uncertain status as Ash's Pokemon. While Haunter decided to join up with Ash in Lavender Town and journeyed with him to Saffron to take down Sabrina, he was never officially caught within a PokeBall. Furthermore, while the show has included many of Ash's past Pokemon as cameos in later Openings and Endings, most memorably Spurt which featured basically every Pokemon of his up to the Battle Frontier season, his Haunter has never made a single appearance. So, it seems that the writers ultimately either forgot about Haunter, officially consider it Sabrina's now and thus in the same position as his Ambipom, or was never considered Ash's Pokemon whatsoever, and was equivalent to Jigglypuff who just followed the gang around out of its own will. Basically Haunter doesn't stand a ghost of a chance to ever appear again.
#094 - Gengar
Ghost/Poison
So, Gengar, the Final Link Evolution. Where to start with this guy? Well, as the first fully-evolved Ghost Pokemon, Gengar was always quite powerful, and even today still remains an OU Pokemon---I believe one poster said earlier he's the only Pokemon from Generation 1 to keep this status alongside Starmie. While I think Haunter's design is superior to Gengar, I still like Gengar, and I don't think the aesthetic gap is as wide as say, Graveler and Golem, or even Machoke and Machamp, where I think there's a clear, objective downgrade. Gengar is well put together and doesn't add anything unneeded or throw away anything important, he's a very natural feeling evolution to Haunter, I just like him a bit less. As I mentioned in Nidorino's entry, a Pokemon resembling Gengar appeared very early on in the prototype "Capsule Monster" sketches, and this is likely the reason he was included in the original Red and Green opening.
Oh, and he's Ken Sugimori's favorite Pokemon...kind of. You see, a lot of people sort of miss the context of that article about returning to simplicity and use it to push forward the notion that the older Pokemon were objectively superior. Now, it's fine if you think that, and I've made some arguments so far in this thread that supports that notion even though I have plenty of later favorites, but don't use Sugimori's words as proof that even the designers feel that way. I've seen people online basically take that article as Sugimori saying that Gengar is the perfect representation of simplicity which the later Pokemon lack, when he basically just said he enjoys the Pokemon because, as an artist, it's easy to draw and has a pleasing, streamlined design. Most folks don't bother mentioning that right after the Pokemon he criticizes for being complex is Venusaur, a classic Pokemon, so the article shouldn't be taken as a dig at later Generations like I've seen some sites report it as. Even if Sugimori doesn't like the later Pokemon, I don't think that should necessarily influence the fans' opinions either---it's okay to like something that the creator dislikes, just like it's okay to dislike something the creator says is his magnum opus. Judge works by their own merit, not because others tell you how to feel about them, even if they have some "authority" due to being involved with the work. Anyway, enough pontificating, let's talk about Gengar!
Visually, you can see Gengar as resembling a Haunter who was able to materialize its entire body in our dimension, possibly due to the use of the electrical energy that seems to occur when Pokemon are traded. Perhaps it would've been more effective if Gengar fully resembled Haunter with the addition of extra body parts, to really hammer this point home, but I can understand Game Freak wanting to make Gengar a bit more distinguishable by changing minor elements of its design such as its hands and eyes. Giving Gengar those big, clawed hands as opposed to the cute stubs he has just wouldn't look right, now would it? Despite being a Ghost-type Pokemon, and a final evolution, Gengar's quite adorable, probably the cutest member of his line in-fact, and as a kid I had this awesome little foam doll I got at Disney World of him. But I was a weird kid, and had a bad habit of chewing on toys when I was bored, so poor Gengar didn't last long. A precursor to his eventual weakness to Bite and Crunch, perhaps?
As his name suggests, Gengar is inspired by the mythological doppelganger. There's a lot of different stories about such entities, but a common thread is that they resemble an individual so much that they can be mistaken as one's "evil twin", and also usually seeing one's doppelganger is a foreboding sign that misfortune is soon to follow. Gengar takes the appearance of one's shadow, stalking them throughout the night, and performing various misdeeds out of a twisted sense of fun, so it's definitely a Pokemon whose appearance isn't cause for celebration. Gengar is basically a shadow itself, capable of using them as a mode of transportation yet oddly enough he's unable to learn Shadow Sneak, the one move that best represents this ability. There's a popular theory that Gengar is specifically the shadowy doppelganger of Clefable, due to their similar appearances and relationship with the moon, but to be quite honest I've never given this much thought. As I've demonstrated, many Generation I Pokemon share similar appearances likely due to being developed by a rag-tag group with a probable deadline, so I feel it's probably a coincidence and nothing worth looking into. At the very least, no official media has ever specifically placed Clefable and Gengar together, so for now it remains a fan theory.
Wherever Gengar is, the temperature is said to drop as it absorbs its victim's body-heat, which is based on a popular paranormal phenomenon known as the "cold spot", in which ghost absorb heat energy in order to materialize thus causing a sudden, unexplained drop in temperature in a specific area. Wikipedia specifically says that "cold spots" are defined as 10 degrees colder than the surrounding area, which is a condition that Gengar roughly meets according to its Diamond PokeDex entry. Of course, this violates the laws of thermodynamics as any skeptic will tell you (don't ask me how it violates it, it just does), but it makes for a cool Pokemon ability. Unfortunately, Gengar's never really taking advantage of this little part of its lore though due to learning very few Ice-type moves, and only through breeding and tutors. Maybe it's time he picked up at least one Ice-type attack as part of his natural moveset such as Icy Wind? Oh, but after he learns Shadow Sneak of course.
Gengar was always popular outside of the main games, such as being the primary antagonist of the original Pokemon Mystery Dungeon who successfully played everyone like a fiddle, but recently got a big boost in popularity due to appearing in Pokken Tournament as a playable fighter, the winner of a poll to decide which Pokemon would be included if I recall correctly. Well, there are plenty of other Pokemon I would've chosen for a fighting game, but Gengar's theatrical style certainly looks visually pleasing, and from what I understand I believe his character ranks highly among Japanese tier lists at this point, although it remains to be seen how the rest of the world will feel about him when (if?) we get the home version of Pokken Tournament. We...are going to get it, right?
Like Nidornio, Gengar was one of the first Pokemon to appear in the show mimicking the opening of Red and Green. Apart from that Gengar's made many appearances throughout the show, but played second-banana to Haunter in its true debut. As one of the most powerful Pokemon in the game, it's made a lot of major battling appearances under the command of Agatha, Drake (the Orange Islands dude, not Hoenn Drake), Morty, and Fantina, and usually proves to be a pretty effective opponent for Ash. Except for Fantina's who lost to Buizel of all things, but to be fair that was Diamond and Pearl Ash where he was totally based and capable of going up against Legendary Pokemon.
#M094 - Mega Gengar
Ghost/Poison
Like its buddy Alakazam, the already powerful Gengar got even more powerful with its own Mega Evolution! Really feels like Golem and Machamp should've gotten these Mega Evolutions though since they actually are in need of a power boost to compete with the newer Pokemon, but hey, it's not my decision so don't blame me. Apart from HP and Attack, Mega Gengar experiences a rise in the rest of its stats, especially its Special Attack which puts it among the Legendary Pokemon---the only non-Legendary Pokemon with higher Special Attack is its buddy Mega Alakazam. In addition, Mega Gengar now has Shadow Tag, meaning the opponent is unable to escape---unless of course they're another Ghost-type Pokemon. Shadow Tag is quite fitting for Gengar, and an Ability he probably should've had before Mega Evolving, but of course Game Freak has this weird hang-up about giving Levitating Pokemon alternate abilities for whatever reason. By the way, Shadow Tag in Japan is "Stepping on Shadow", and seems to reference the "shadow stitch" technique made popular by Naruto's Shikamaru. Of course, Naruto didn't invent that, and controlling a person by stepping on one's shadow seems to be a popular myth in Japanese media as years before a character in YuYu Hakusho was capable of doing that, and I'm sure there's even older examples in Japanese literature.
Now, Mega Gengar is an obvious improvement stat-wise, but how about looks? Well, I'm not gonna lie, I think it's a step-back, and general opinion seems to agree with me, although most people have taken a liking to it and it's certainly not the most hated Mega Evolution. By the way, have you ever seen the underside of its model and its tiny legs? If you want to still like Mega Gengar, don't look that up as it'll ruin the design for you. I do like Mega Gengar in general, though, because I like how his slanted design makes him resemble a shadow being cast off an object, and I do like some of the elements of Haunter that have snuck their way back in, but I think the biggest flaw is making him way spikier looking than he should be. If Mega Gengar kept the slanted appearance, but basically looked like Gengar without all the pointless spikes, I think he'd be slightly better received. Mega Gengar also grows a third eye, which really wasn't present or alluded to in any of his previous sprites and models, but is said to allow him to peer into other dimensions, possibly his homeworld, and I think fits his design pretty well. Perhaps the third eye concept should've been used on Mega Alakazam, though, given its association with psychic abilities...
Mega Gengar has only made a cameo appearance in the Mega Evolution Specials, but is featured in Pokken Tournament as Gengar's Mega Evolution.