Verified answer

A chainsaw but my parents learned the hard way

-kidding-

A Horse

The mistress --- She should be kept in a tent on the back lawn and thrown a few crumbs now and then

A horse

Uninvited guests

Those not useful/broken things such as broken appliances, broken furniture, garbage, old newspapers, advertise mails, old and broken clothes or personal stuff.

Aye! A ship anchor Matey. Yo Ho! :D

Baby poison!

Hm any large animals or alligators!

Anything that Dexter has. He's a crazy man..