Dragon Ball Z Kai (2009)

S6E15 Rescue Gohan and the Others! Goku and Vegeta's Infiltration Mission!

Trapped inside Majin Buu's body, Goku and Vegeta split apart from their fused form. Shielding themselves from the creature's attempt to fully absorb them, they navigate the monster's inner landscape. With time running out, the two Saiyans search desperately for a weak point, hoping to destroy Buu from the inside before it's too late.