One of these came too near my base (it was made of thatch...)... it saw me, killed my newly tamed dilo and parasaur (even after I had to replace my other dilo and parasaur from a trike) while my moschops ran away. It destroyed my base, basically.

A few days later...

Oof, a new server to start on! Yay! Why does it say my moschops died? What moschops? Whatever... oh, this looks like the area I built my base in on that other server. Sees some thatch... oh my gosh it is that server.

It literally tore through my thatch walls and floors, to get to my storage boxes, destroyed and looted them, why?

For low levels: RUN FOR DEAR LIFE

For high levels: spam the kill for revenge