Dabura is the king of a Demon Realm, and Babidi's right-hand man, being placed under his control by a spell. Dabura has the special power of turning his enemies to stone, simply by spitting on them. His name is originally taken from a Japanese pronunciation of the last half of the incantation "Abracadabra".

Spoiler

He fights Gohan in both his normal and Super Saiyan forms to gather energy for Buu, but before they can finish, he notices Vegeta has evil within him. During the fight Vegeta shows great frustration which comes from the fact that Gohan has to make an effort to kill Dabura even though Gohan is still more powerful than Dabura. This spawns from the fact Gohan has not trained at all in the past 7 years and is only slightly more than half as strong as he was when he fought Perfect Cell. This allows Babidi to grant him power. When Buu is released, Dabura tries to kill him, but is turned into a cookie and devoured by Buu. (Upon his death in the anime, King Yamma decides that the usual punishment of exile to Hell is what Dabura would actually desire, so he instead sends him to the most peaceful region of Heaven.) In the anime, Dabura is later seen wandering as a "good-spirited" soul consumed with love (creeping out anyone who meets him).

It is mentioned by Goku that Dabura's power is equal to Perfect Cell's. Source - Wikipedia.