Based on the viral “creepypasta” series of internet-based stories from writer Elias Witherow, The Third Parent takes place amidst a Fourth of July celebration when a disturbing figure named Tommy Taffy emerges, disguising himself as a human to infiltrate a suburban neighborhood and impose authoritarian rule over an unsuspecting family. Starring Rob Lowe, Crispin Glover, and Roselyn Sánchez.