Online Ur and to a lesser extent regular Ur from Dragon's Dogma. This is mainly due to Capcom's terrible camera, animations, and the climbing in the game. The climbing works well in the game, but there are many points on Ur that make it a pain in the ass.
god I hated those, I wish I can play morrowind again just to pay respects to jiuub or however his name is spelt (guy on the boat with you at the beginning of the game) read somewhere in the elder scrolls wiki that he ended up hunting them to near or complete extinction
and well im just going to say zubats or any other enemy in a random encounter type game that is overly abundant in areas. being easy to beat doesn't make them any less annoying
Banshees from mass effect three as a vanguard. The only enemies that were actually hard because you couldn't just ram into them without getting punched through the chest. Other than that it was like GOD mode.