A slime

Ahead in a shallow dipped area is a moving mass of liquid, rolling slowly to you. You realize this thing must be what your mentor had called a slime. Sadly, you don’t remember anything else about them, as your mentor made it seem like they weren’t a big threat.

Your instincts say to take it out while you can, but you don’t know if it’s actually hostile, or if your knives are even effective.