If Sundance crowds couldn’t handle Daniel Radcliffe as a farting corpse, wait ‘til they get a load of the pasty potbellies, bulging man-panties, lard-licking psychotics, and squirmy full frontal sexcapades of The Greasy Strangler—the first true WTF film of 2016.

Father-and-son weirdos in matching turtlenecks and short-shorts lust after the same...