- Pretty much any enemy in Lightning Warrior Raidy that has either a magical or fire breath attack, because armor doesn't reduce the damage they incur. Adding to the annoyance is the fact that you can only restore health with potions, meaning that you can survive the battle and still hurt your long-term game plan because you took so much damage beating them.
- In D/Generation, the C/Generation (predecessor to the title entity) is a dark, shape-shifting humanoid that will hide as a file cabinet, fire extinguisher, or another human until you walk close, at which point it will transform, give chase, and decapitate you even if it has to follow you onto another screen. If you don't have any grenades (likely that you wasted them all since you can only fire in four rigid directions), the only way to kill it is to run through some environmental hazards and hope that it gets hit and you don't.
- The fairly-obscure Puzzle Platformer Game Boy game Dexterity plays with an overhead view. You need to flip over all of the tiles on the level to advance (which is sped up by sandwiching blank tiles between them). Anyway, the Demonic Spiders are Humphreys, a fast, erratically-moving enemy that can create wall tiles and if you let them do it in the wrong place, they'll wall off tiles that you need to flip. A level late in the game has two Humphreys, making it That One Level.
- Indiana Jones and His Desktop Adventures has the snakes, which attack really damn fast and do a lot of damage. One snake can really wear you down before you realize what is going on, especially when they attack diagonally.
Demonic Spiders / Adventure Games
Demonic Spiders: Proving that adventure is over-rated since the invention of video games.