There's that ultra rare ennemy in the Chalice Dungeons in Bloodborne! If I remember correctly, he wasnn't documented in the guides, but someone discovered it and posted the dungeon code online, so anybody can go pay him a visit!
Very strange mob, too. The head of the creature can travel trough his body depending where you're attacking him!
Holy shit. I have to see that thing myself.
There are a few boss fights in Kingdom Hearts 1 that could be run away from like the 1st Clayton phase (as noted by the barrier appearing in the cutscene between phases) and Captain Hook. This means in the vanilla version with unskippable cutscenes, players didn't actually had to rewatch the infamous "not Clayton" line repeatedly by running from the fight after that line and creating a checkpoint.
Haha yeah, I remember using this back in the day. Tried it again in the PS4 collection recently because Hook was the first boss to give me trouble and yup, still works.