Cooler is the older brother of Frieza and son of King Cold and makes his first appearance in the movie Cooler's Revenge. Cooler and his Armored Squadron went to Earth seeking revenge on Goku for killing his brother Frieza. Cooler was killed by Super Saiyan Goku when Goku did a Kamehameha that pushed Cooler into the sun. Cooler has a later appearance in the movie Cooler Returns as he is saved by the Big Gete Star and gains a new robotic form known as Meta-Cooler. Cooler also appears as one of the ghost warriors in the OVA: Plan to Eradicate the Super Saiyans.
His Name is a obvious pun on cooler, a household appliance.
Coolers's power in his 5th form is higher than that of his father or brother but in 4th form he himself states that he is weaker than his brother, which is further confirmed when Goku is able to near equal him.Cooler can gather energy faster than Frieza. In his fifth form he is easily able to overwhelm Goku, but he is still not powerful enough to stand up to the might of a Super Saiyan, although as Meta Cooler he is able to take Goku and Vegeta even as Super Saiyans without too much trouble.