The Days Are Just Packed (Calvin and Hobbes series Book 8) (2014)

Zounds! Spaceman Spiff, Stupendous Man, the ferocious tiger Hobbes, and the rest of Calvin's riotous imagination are all included in The Days Are Just Packed.
Calvin, the self-proclaimed "Boy of Destiny," continues to save the universe with his alter egos, Spaceman Spiff and Stupendous Man, at least until Miss Wormwood or his mother bring him back to reality. Susie, Calvin's nemesis and love interest, remains Calvin's favorite target. And when he's not recovering from a ferocious tiger attack, Calvin creates hideous snowmen, plays a moral cat-and-mouse game with Santa, conducts his infamous Dad polls, and combats the monsters under his bed.