Orange Slime

The Orange Slime has one move: it slides toward the nearest player and hurts you only on contact. There is no swing or projectile to read, so keeping any spacing at all keeps it off you.

It turns up across the Mole Stronghold and the Woodlands as a common, low-threat spawn. The Giant Orange Slime is the oversized version in the same zones, and the Blue Slime is the tougher recolor that takes over from the Library onward.