Gokle is a monster created by Goku's DNA. A man had collected Goku's DNA and wanted to remake a evil monster to get him money. His plan failed and the monster Gokle turned on him. He was killed on impact of one hit!!! It looked very similar to Vegetio.
Gokle was destroyed by Goten. Goten had so much power in one attack that when he let it go he killed Gokle.