Today while catching bumble bees, I noticed how well it can follow you, and if you are too far it will change targets. So, why not use that same coding for a pet? You can click on the pet in your house, and there will be the name, aswell as a "hostile" button. Toggling that button, your pet will chase guests in your house and attack them. This would be great for household events, games and just for messing around.
My second idea is a companion. He will probably not be implemented into the overworld due to the fact of lag. However, a companion that will actually follow you inside your house, instead of walking two tiles to the right, back one, repeat. This following companion could also have the hostile button, as well as the follow button.