It's time for all-new tricks and devilish treats on THE SIMPSONS annual Halloween trilogy, -Treehouse Of Horror XVI.- The fright-fest begins in - B.I.: Bartificial Intelligence - when the Simpsons adopt David, a newly developed artificial robot son, to replace Bart after he falls into a coma. In - Survival of the Fattest,- Mr. Burns invites Homer and his friends to his gigantic estate for a hunting tournament, but Homer and the gang learn they are the ones being the hunted on -The World Series Of Manhunter- hosted by Bradshaw. In the final Halloween scare, -I've Grown a Costume on Your Face,- a costume contest goes awry when a real witch turns all the Springfieldians into real-life versions of their costumes, leaving Maggie dressed like a witch with the only real power to reverse the spell.