I created an NPC I created that avoids any model with a humanoid that contains “zombie” or “headcrab” in the name.
https://gyazo.com/28e553f87f7b441ec9bab7484ce37042
They also look at players but don’t attack them.
Have fun doing random stuff with it in-game.
also they sometimes run off the edge.
edit : don’t kill them or else too many headcrabs spawn and lag your game and kill you too.