In Gotenks' hands, Super Saiyan 3's insane power is revealed, as at some point during the fight against Super Buu, he and Piccolo are trapped in the Hyperbolic Time Chamber, which Buu sequestered ...

forming "Super" Buu, a tall, skinny and intelligent Buu capable of complex speech and rationality, even before absorbing Piccolo, Goten and Trunks (as Gotenks), Gohan and countless others before ...