Welcome to the dungeon
In this very darkly funny adventure (think way amped up Deadpool humor), Carl is saved from annihilation by aliens because his soon-to-be-ex-girlfriend's prizewinning cat, Princess Donut, has escaped their apartment. While he's freezing outside in the wee hours of the morning, barefoot in his boxer shorts and a jacket, trying to re-capture Princess Donut, Carl sees every physical structure flattened, literally. Anyone who was in those buildings? Gone. He knows that because an alien announcer tells him so.