Mangod said:
Sectopods in XCOM: Enemy Within. In Enemy Unknown they were intimidating the first time, but they fell to H.E.A.T. ammo just like every other mechanized enemy in the game. But the expansion...
So, H.E.A.T. ammo gets nerfed hard, then the Sectopods get a Health buff, and on top of that, they get a buff that halves all the damage they take. Frustrating as **** to deal with.
Ninja'd on that one. Not only that, they also increased their DEF, which made no sense whatsoever. Now for no reason at all, your guys had a harder time hitting them than they did a 3 foot tall skittering Sectoid
X-Com again (old school) but in X-Com: Apocalypse, there were these small little aliens that would see your guys, and then run at you at about 60 MPH and explode. God they were fucking awful (actually, pretty much any enemy that runs at you and blows up sucks).
Any of the Ghost/Spectre/Wraith enemies in "Pillars Of Eternity", who instantaneously teleport right next to your magic users and ranged guys and murder them in about 2 seconds (especially early game).
In Diablo 2, those Goddamn Fetishes in the 3rd act. They moved fast as shit, could breathe fire, always came at you in swarms of about 500, could hit you with blowguns from a distance or knives up close, and the final cherry on the shit sundae: they had Shamans who would resurrect the dead ones while you were fighting them.