This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Beat the Clock
When the animated "Hickory, Dickory, Dock" opening was introduced on December 20, 1952, it had three parts: the first segment had the mouse and logo-Clock, while the third had the logo-Clock's hand wiping around to show various Sylvania products. The second part was shots of people laughing against a dark background with odd music playing; while ostensibly meant to be people laughing at the show's silliness, viewers found this segment unnerving, and the laughing portion was excised beginning on February 14, 1953.