Other source:
In an attempt to abort the hatching, Gohan begins firing Kamehameha waves at the ball, but it doesn't seem to do much good. The ball opens, but after some pink steam escapes, there is nothing left in the ball. They believe that Gohan destroyed Buu with his energy blasts, but suddenly the pink steam begins to congeal. It forms into Majin Buu. Instead of a fearsome beast, Buu is a fat, pink child, but Shin knows that it is really Majin Buu and not something else. Goku and Vegeta have noticed the sudden upsurge in power, and realize that Buu has been hatched.
