The world around us is a far more weird and wonderful place than most of us ever realize. Below are a few peculiar items lifted from YouTube to spark your creativity. I'm already thinking up a scenario that combines all of these critters into a set of linked encounters...
Ouch. Enough said.
These are shrimp for crying out loud...Shrimp...save versus shrimp? The thing just snaps its specially-modified claw and the resulting implosion of air bubbles temporily reaches the temperature of the surface of the sun. You can't manage that with a Zippo lighter at a Lynnerd Skynnerd concert. (Freebird!) Anyone making-up this sort of critter would very likely get laughed at and then punched. Hard. Repeatedly. But it's real, and now you have proof of it courtesy of the BBC.
Drunk Monkeys. Another denizen lurking in some dimly lit corner of an inn, bar or gin-joint near you--some of them aren't just drunks, though, some of them belong to thief-troupes...and they might have friends amongst the roving bands of Rogue Baboons...
Breakdancing skunks, or could it be olfactory capoeira? That's some dance of defiance.
Okay, maybe these would work just fine, especially if they were enlarged and perhaps trained by some sort of aquatic being to serve as guards along the shoreline or in the midst of a really big mangove swamp...best not be carrying a lantern near that pool...
Now this is just too good not to use for an encounter. Wonder who'd train and use such critters as mounts? A good critter to summon for a quick get-a-way as well, if you can call up a big enough specimen...
Parasitic fungi that infect the victim's body and mind--and it's real--and there are over a thousand vrieties that are out there, possibly one that can convert PCs into weirdly elegant sculptures. It's not just Yuggothian Mi-Go that you need to worry about...
Let me know if you found any of this useful.