Father and Son Kamehameha

After Goku sacrificed his own life in order to save Earth from Cell, Cell managed to survive the devastated explosion in King Kai's Planet, killed Trunks, nearly killed Vegeta and severed Gohan's right arm badly. As all hope was seem lost, Goku managed to communicate with his son and encouraged him to give Cell the biggest Kamehameha wave in order to avenge those that Cell killed.

Gohan: Ka... me... ha... me...

Cell: Now... you... DIE!! (He fires his Kamehameha wave)

Gohan: HA!!!! (Gohan engages on a beam struggle)

Goku: Release it, Gohan! Release your true power! Remember the people he hurt. Make him pay!

Cell: NOW DIE, SAIYAN!! (Interrupted by Vegeta's Big Bang Attack) Vegeta!

Goku: Now's ur chance!!

Gohan: HAAAA!! (Cell was slowly disintegrated)

Cell: This... is... impossible! (He dies completely)