If you are a new player, just spawned in, dont have any armor or clothes, NO TAMES, they will protect you if you are attacked. This is from my experience though, my game might be bugged. Though they will attack your tames. This goes with the enforcer as well.
These things will destroy any and all structures you put in front of them. They can and will destroy metal as well as tek. Nothing is safe from these things. If you are on Genesis lunar biome these things are everywhere along with the flying ones. Be careful out there guys.