Broccoli's Sweetheart?

REBORN! – Season 1

Kyoko's friend Hana is infatuated with Future Lambo and blackmails Tsuna into letting her meet him by threatening to tell Kyoko that Haru is his girlfriend. When Lambo uses the Ten-Year Bazooka, however, something malfunctions and creates a teen Lambo with young Lambo's mind, and to make matters worse, this Lambo escapes from the house.