The Matchmaker / The Grades

S5, E112: Darwin likes a girl in his class so Gumball decides it’s time to play cupid. / Miss Simian discovers a failed test from Gumball's past that brings down his grade point average. This means he has to retake kindergarten all over again, much to her delight. But by demoting him Miss Simian has inadvertently brought herself down, and they're left with no choice but to team up if they want things back to normal.