Who defeated Buu in DBZ?

Back on Earth, Tien arrives to back Gohan up, but after a short battle, Buu easily disposes of him. Meanwhile, Goku prepares to teleport back to Earth, but Old Kai tells him to wait and gives him the Potara earrings, which will allow him to fuse with Gohan and defeat Buu.

Who can beat Majin Buu?

Even with his Super Saiyan 3 power, Goku already possessed enough strength to defeat both Majin Buu. His Super Saiyan God transformation would be more than enough to reduce even Kid Buu to a lifeless pink blob.