elder seal
Wouldn’t fit in my last post.
Centipede- looks like the caterpillar except with way more arms and can dig up to the surface and tunnel under it.
Brainiac- looks like a puffy but has a large head or large brain for a head. Can manipulate objects and use a spear. Will bash your walls with a rock instead of body slamming them.
Dragon- large flying mutant. Looks like a pterodactyl. Can carry you away if you’re not wearing armor.
Peeper- puffy with giant eyeball for a head. Doesn’t attack if you’re wearing creepy armor, probably thinks you’re a mutant. Will direct other nearby mutants to your location.
Bloatey- looks like holey but no holes. Will wander up to your base and explode, putting a hole in the wall, knocking you down, and spawning a few babies.
Siren- looks like an octopus. spawns in lakes and screams. Will grab you and pull you underwater if you’re swimming over it. Good luck if you haven’t found the rebreather yet.
Humpback- large and slow puffy with a giant cyst on its back that emits pheromones to call other mutants to your location. Pheromones make you sick and limit your max health when in radius. Shooting the cyst with a shotgun or explosive arrow would cause it to explode, killing the humpback. An interesting weak spot.
Feel free to add more suggestions or roast mine.
frosty echo
urban wyvern
flint flame
desert lance
naive mica
weary fjord