7x15 - Dragon Ball Z: Dragon Box

At Boo's request, Trunks and Goten once again undergo Fusion. Just as Gotenks turns Super Saiyan 3 and is about to start fighting, a pink object envelops him. Boo's strategy was to absorb Gotenks and Piccolo, using a portion of his body that he had previously detached! After taking the two of them and assimilating them into his body, a powered-up Boo once again starts attacking Gohan!