First, Super Janemba places his hands at the sides of his face as he charges a green energy sphere in his mouth. Then, he yells and fires the green energy in the form of an energy wave (or as an energy sphere) from his mouth at the opponent, inflicting a high amount of damage.
Super Janemba uses this attack during his battle against Goku in his Super Saiyan 3 form in Dragon Ball Z: Fusion Reborn. After teleporting away to evade Goku's energy attack, Super Janemba reappears and blasts Goku away with an attack of his own. Super Janemba then fires the Hell Gate energy wave at Goku, blasting him away and destroying most of his shirt.
Video Game Appearances
The attack is called Chou Makouhou in the Budokai Tenkaichi series, where it is one of Janemba's Blast 2 attack and is also the finishing blast of his Dimension Sword Attack. It is called Super Breath Cannon in Dragon Ball: Raging Blast 2 and Dragon Ball Z: Ultimate Tenkaichi, and it received its own name Hell Gate in Dragon Ball Z: Infinite World. Hell Gate is also Baby Janemba's special attack in Dragon Ball Heroes. It is also a basic blast used by Super Janemba in Dragon Ball Z: Shin Budokai - Another Road. The technique also appears in Dragon Ball Xenoverse 2 as part of one of Janemba's basic attack combos. In Dragon Ball FighterZ, Hell Gate appears as one of Janemba's aerial super moves where he fires a small energy sphere from his mouth the trajectory of which can be altered with Up input and the sphere can be detonated by imputing the same command used to fire it.
In the Dimps video games, the attack is performed differently. He lifts up both of his hands at the side of his face and fires the blast from his hands.