#602 - Tynamo
Electric
Tynamo is the rarest Pokemon in Chargestone Cave and could be seen as a parallel to Magikarp, though rarer, due to having an extremely limited movepool and poor stats until it evolves---unlike Magikarp it can learn TMs, but only moves that it learns naturally anyway, and happens to have two evolutions as opposed to one. It's not quite as weak as Magikarp however, but it's the closest analogue to it among the Unova Pokemon which surprises me since it seems like an archetype Game Freak would definitely seek to emulate 1:1 again. The unique thing about this family is that they always have Levitate removing their weakness to Ground, their only weakness, and thus as of Generation VI they've become the only family to lack any weaknesses under normal conditions since Sableye and Spritomb became weak to the Fairy-type, and unless Electric suddenly gains a new weakness this probably won't change anytime soon.
I love this line because they appear to be based off of sea creatures, but aren't actually of the Water-type and Game Freak needs more of that---instead it seems to "swim" through the air. Personally I think a later Pokemon handles the non-Water fish motif a bit better by still living in water, which Game Freak should do more to diversify Pokemon you'll find while surfing or diving, but it's a step in the right direction and another example of how they appeared to realized Water-types were getting a bit out of hand---though then again this Generation pretty much made rain teams pretty overpowered. There seems to be two camps when it comes to this line, are they eels, or are they lampreys, though I think the line incorporates elements of both with the lamprey elements coming into play when it evolves but at this point it appears to be a leptocephaelus, the transparent larval form of certain eels. Though its electrical abilities of course bring to mind the electric eel, but that isn't actually an eel despite the name but rather a knifefish. When it was first revealed I also thought it was supposed to be a rod, otherwise known as skyfish, which are artifacts that appear on film which have been thought to be by some circles cryptids or extra-terrestrial lifeforms. Notice it also happens to resemble one of those electrical tubes you see in generic labs---and it kind of looks like sperm too.
Despite not using one in the games Tynamo ended up being Elesa's ace Pokemon in the show when she was fighting against Ash, and while it proved to be very fast and surprisingly powerful with Tackle one hit from Pikachu's Iron Tail managed to take it out. God, I want to forget Elesa's Gym Battle.
#603 - Eelektrik
Electric
At Level 39 Tynamo evolves into Eelektrik and finally becomes capable of naturally learning moves---an ability it immediately loses again if it evolves since it evolves via an Evolution Stone. Though it'll miss out on a few of its earlier moves it learns prior to Level 39, it learns some useful ones further on up and actually has decent stats now to take advantage of them and its lack of any weaknesses. I think its kind of funny how the level cap has moved up so much where Magikarp evolving at Level 20 was seen as a decent challenge to score Gyrados, but here you almost have to raise Tynamo to twice that amount to have it evolve into a weaker Pokemon.
But Eelektrik is one of those Pokemon who is easy to forget because it's squeezed between two more interesting Pokemon, plus seeing Tynamo as the Magikarp-equivalent most will think off the top of their head it only has one evolution where it receives a respectable power jump as opposed to two---I wouldn't be surprised if there are folks out there who think it goes Tynamo -> Eelektross. While Tynamo mainly seemed to be an eel here Eelektrik takes on a more lamprey-like appearance with its circular-fanged mouth, though despite lampreys popularly being seen as sucking the blood of their victims (most actually don't) it's a bit of a shame Game Freak didn't give it Leech Life. This family starting with Eelektrik becomes a bit infamous for their divisive Gen V/Gen VI animations, with Gen V showing them bouncing on the ground while Gen VI, like the majority of Levitating Pokemon, have it floating through the air like its Ability suggests it would move like. Some like the former, some like the latter, and the argument only gets more heated upon its evolution. Doggie mentioned earlier in the thread that only the localized name includes "eel" but he's incorrect, the Japanese name is usually romanized as "Shibibeel" and thus seems to include "eel" as well.
Eelektrik popped up in a small Tournament near the end of Best Wishes and was taken out by Pikachu like in a single frame. That's it.
#604 - Eelektross
Electric
Eelektrik evolves into Elektross through the use of the Thunder Stone, the first and only Pokemon to do so since Pikachu and Eevee in Generation I. Ghetsis uses one when you fight him in Black and White and the sequels and I recall it being rather difficult, lacking any weaknesses and having a pretty diverse movepool to deal with. While it can be dangerous offensively, it's held back a bit by its rather slow Speed and despite lacking any weaknesses it also doesn't have too many resistances so fast and offensive Pokemon shouldn't have too much trouble dealing with it, but you'll still need to be careful around it because as mentioned before for an Electric-type Pokemon its moveset is fairly diverse. As much as I think Levitate is part of its character, and helps it in a lot of ways by making it resistant to Earthquake, Spikes, and Toxic Spikes without the drawback of being weak to Stealth Rock, it's one of those Pokemon that perhaps would also be interesting if it got a different Hidden Ability to mix things up, perhaps one that could curb its low Speed a bit more. But now that it's the sole weakness-less Pokemon I don't see Game Freak changing that anytime soon.
Despite being such an unorthodox design Eelektross is another Generation V Pokemon that seems to be a fan favorite, probably due to his unique gameplay in addition to his iconic appearances under the command of both Ghetsis and Emmet in Black and White. It becomes even more of a lamprey-like creature, capable of using its teeth to deliver powerful electric shocks, though it also begins to take on a somewhat reptilian-appearance with the introduction of rudimentary arms and flippers that in the official art and Generation V seemingly can function as legs allowing it land mobility. It seems Game Freak didn't really think much about where this Pokemon lives, in Black and White only Tynamo could be found in a completely dry area though in Black 2 and White 2 it and Eelektrik could also be encountered in the Seaside Cave living near water. According to the PokeDex it seems Eelektross is amphibious as it is said to be capable of crawling out of the ocean to attack its prey, and thus you have to wonder why it has Levitate since it doesn't really fit it mechanically. In Generation VI, so it can compete in Sky Battles, it's always shown floating through the air like one of those Japanese fish wind socks but it really just looks more like its swimming such as the majority of fish-based Pokemon do---I'm interested if at one point this family were actually part-Water with its removal and Levitate elements added late in the design phrase and not an inherent part of this Pokemon's design from the get go.
Eelektross appeared in the show under the command of Emmet, his signature Pokemon (and it seems most fan works depicts it as such as well) and was used to help power a maintence car allowing him and Ingo to catch up to Team Rocket who had hijacked a subway car and later had a friendly battle against Ash's Tepig and Cilan's Pansage alongside Ingo's Chandelure, quickly defeating the two of them with Thunderbolt after Chandelure immobilized them with Psychic. Later one had a small appearance in the Unova League where it was taken out by Cameron's Ferrothorn.