Bellerophon was one of the greatest mythical heroes in Greek history. His major accomplishment was slaying the Chimera, a fire-breathing monster with the head of a lion, the body of a goat, and tail of a snake. He is also known for flying Pegasus, the winged horse.
Legend says that Bellerophon became arrogant as his fame and power grew. He was amazing but he wanted more. He thought himself deserving of a seat among the gods on Mount Olympus. When he tried to fly to Olympus himself upon Pegasus, Zeus was bothered by this, and so Zeus send a gadfly to bite Pegasus. The horse was startled and Bellerophon fell back down to earth.
- https://en.wikipedia.org/wiki/Bellerophon