Here's the second enemy on the list. Another fairly harmless walking thing. From what the developers have told me most enemies can be defeated by jumping on them, but when you get close to it this happens.
Probably best to leave it alone. In the demo they actually chase after you even if you jump past them, not sure if that will stay the same in the end product though. Almost every platformer/adventure game I can think of off the top of my head has something like this though, as annoying as they are.