If there’s one thing to take from “Butt Boy,” director Tyler Cornack‘s dark, stomach-churning tale of a serial killer who uses his anus as his weapon of choice (yes, really), it’s that playing a silly idea as straight horror can work. This kooky and wildly weird movie will exceed the needs of its very, very small niche audience: those fans of deranged midnight cult flicks and deadpan, exceedingly dry indie humor. Bored IT engineer and suburban dad Chip (Cornack) dreads his first prostate exam. After he assumes the position on the exam table, Chip has an awakening and takes great pleasure in...