Wop Grease
The unfortunate practice in a video game, usually a platform game, where the character you're controlling can make a jump no problem, but lands and somehow slips off into the abyss. Gets its name from being introduced in Super Mario Brothers, as you character is an Italian plumber and the stereotype that Italians are very greasy
I would've beaten World 8-1 no problem, but Mario slipped on his wop grease making that one jump and I lost my last life.