Gregory is a little flying cricket and King Kai's motor-mouth pet. Gregory is very respectful of his master and always speaks highly of him, but he will talk trash to anyone he does not believe is better than him. King Kai called for him after Goku managed to catch Bubbles: the new goal was to hit Gregory with a heavy hammer. Much later Gregory is killed when Semi-Perfect Cell blows up on King Kai's Planet. Source: Dragon Ball Wiki