Sitcom crossovers used to be a major TV event, bringing beloved characters from different worlds together for unforgettable moments. From George Jefferson on The Fresh Prince of Bel-Air, to Steve Urkel on Full House, to the New Girl & Brooklyn Nine-Nine mashup—these crossovers gave fans something to talk about. But in the age of streaming, network rivalries, and an overwhelming amount of content, the sitcom crossover has all but disappeared… until now. Enter It’s Always Sunny in Philadelphia & Abbott Elementary. This unexpected crossover proved that, when done right, sitcom mashups can still be magic.