"Sleeping on the job, Super Saiyan? I can gather energy a lot faster than my brother. You shouldn't have taken your eyes off me! Now die with this planet!"
Supernova Cooler is a variant of the Supernova utilized by Cooler. The user raises his hand and gathers their energy in the form of a giant yellow-orange, sun-like energy sphere. Once it is ready, the user launches the attack against the target. Like the normal Death Ball, it is mostly used to destroy planets, or as a last ditch-effort to kill an enemy.
When Cooler's final form proved to be too much for Goku to handle, Goku's rage and desperation transformed him into his Super Saiyan form. Battered around and overpowered by Super Saiyan Goku, Cooler launched his Supernova, intent on destroying Goku along with the Earth (he even mentions he can gather his energy much faster than Frieza). However, Goku manages to push it back with a Super Kamehameha, sending Cooler and his Supernova into the Sun, and it seems that he is destroyed.
"Toss a huge, power-packed Ki Blast at your opponent!"
— Dragon Ball Xenoverse 2 Skill description
This technique appears as Cooler's signature Ultimate Skill in Dragon Ball: Xenoverse 2 where it is named Supernova Cooler. It is similar but separate to Frieza's in-game Supernova technique, being darker in color and is created and thrown utilizing a full hand instead of a single finger. It is used by both Cooler (in all his forms) and Metal Cooler.
"Fires a massive Ki Blast."
— Dragon Ball Xenoverse 2 Tutorial description