Spore Zombie

Surface mushroom biomes are the only place these appear, and unlike ordinary zombies they do not wait for dark. Put a house on mushroom grass and you will have them wandering up at midday. They also open doors all the time rather than only during a Blood Moon, so a surface mushroom base wants platforms and elevation instead of a door and optimism.

Plain zombie behavior. It walks at you, paths around ledges and gaps reasonably well, and hurts you by touching you. There are two sprite versions with slightly different builds, but they play identically. Expert Mode never gives it the armed variant that regular zombies get, so it stays a pure melee walker at every difficulty and there is nothing incoming to dodge.

Underground, the same biome runs the Spore Skeleton instead, so the two are effectively the surface and cave halves of one idea.