I played a lot of PC games, mostly not-that-well-known ones, growing up, and looking back, there were some pretty odd choices in enemies. Here are five odd enemies from five different games I played way too much.
From suction cup-based platformer Cosmo's Cosmic Adventures, we have the Red Chomper. This low-rent Goomba upped the head-on-legs ante by adding antennae and a nice set of teeth, but it died just as easily - after only one jump on its head (body?) all the same.
Classic TBS game Heroes of Might & Magic 3 was certainly a fantasy stew - as with all M&M games, it took bits and pieces from just about every monster source and then some - but its depiction of Gorgons as some kind of green scaled cow was certainly... inspired. You may know the Gorgons as Medusa and company, but New World Computing said, "Unless you can give me 305 good reasons to not make Gorgons into green scaled cows, they're going in." Sadly, only 304 reasons came in.
Commander Keen was a classic PC platformer. They made a version where most of the enemies are sentient vegetables. While I've chosen an angry sprinting broccoli here, I could've gone for the vicious parsnip instead. If only there were more such pictures online.
ZZT was an important game for me. Sure, it didn't look like much - it's All ASCII All The Time - but it had a level designer with code windows (in "ZZT OOP"), my very first coding. The game was heavily constrained by ASCII's constraint, but they made bears into brown Os with umlauts, and lions into red omegas, which worked quite well. Why tigers are cyan pi symbols that shoot degree signs at you... no mortal can say.
The above picture says it all.