Help with mob attack

I am trying to make a mob that is summmoned that attacks hostile mobs, currently it will chase after them but I can't do anything to get it to attack them.

I have looked at similar forum threads and most of them say to add "attack on collide," but I do not see that option anywhere. I have tried setting it to iron golem AI, but that makes it move slow and make the walking sounds of iron golems. I also have tried setting it to spider AI (the model it is based on), and I don't see a way to stop it from attacking the player, which I don't want.

What can I do?