Death Ball is Frieza's ultimate attack, where he lights a spark of energy on his index finger. Once enough energy is gathered, this spark may grow to the size of a small moon and is thrown towards the target. Typically, this attack is used to destroy planets or as a last-ditch effort to kill an opponent.Frieza used this technique to destroy Planet Vegeta and Planet Namek in the series.
Frieza also used another variation of this attack to destroy Planet Namek; it was different in size, shape, and color though, likely making it not a "true" Death Ball, though it could easily be explained by Frieza holding the bulk of his power back to avoid being caught in the explosion and the risk of injury. To reflect on this lack of power, neither lightning nor screentone that was applied on the "true" Death Ball that Frieza conjured to destroy Namek in a fit of rage before Goku's ascension to Super Saiyan. He also uses both hands to create and throw (instead of just his index finger).
SupernovaThe strongest version of Death Ball, this was to be Cooler's trump card versus Goku in the film Dragon Ball Z: Cooler's Revenge and, unlike Frieza's version of the supernova, Cooler's can be created near instantly, but his attack is pushed back at him and he is subsequently pushed by the force of it and Goku's Kamehameha into the Sun.
In the film Dragon Ball Z: The Return of Cooler, a Meta-Cooler uses a lesser version of the Death Ball while fighting Goku on New Namek; this was dodged via Instant transmission. Even though Cooler calls it Supernova, when Frieza used the attack to destroy Planet Vegeta, it took on the same appearance, probably meaning that once it reaches a certain size it becomes glowing orange, whether it is used by Cooler or Frieza.