Big Tree Cannon
From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Trunks extends his arms to his sides and forms two golden energy spheres. He then brings his arms to his front and fires a large golden energy wave at his opponent, inflicting a high amount of damage.
Dragon Ball Z
Trunks used this attack in his match against Son Goten at the 25th Tenkaichi Tournament. Later, Trunks (who was with Goten in a Mighty Mask disguise) used this attack again in an attempt to blast Artificial Human No. 18 out of the sky.
Big Tree Cannon is named in the Budokai Tenkaichi video game series and is Trunks' Ultimate Blast in his Super Saiyan form. It is also Gotenks' Ultimate Blast in his base form and one of his Blast 2 attacks in his Super Saiyan and Super Saiyan 3 forms.
It is named Kiaihō (気合い砲, Kiaihō) in the Butōden video game series, Double Buster (ダブル バスター, Daburu Basutā) in the Budokai video game series, and Daburu Basutā (ダブル バスター, Daburu Basutā) in Dragon Ball Heroes.