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He was first best friends with Nelson they do have same interests and dreams in life. They both work together when they are kids in Science. But after Nelson Nefario discovered when they are 20 years old that Mario is evil they had a fight and after, they became enemies and this makes them work harder in inventions and expirements. Mocker did lots of evil things, mutating creatures, invading cities, starting wars at different places and many more stuff. After manyyears,a day come where Nefario finished his invention where he can kill Mocker for revenge. Mario Mocker is then believed dead and Nelson Nefario stayed with his family then later on become Gru's gadgeteer. After getting over with Vector Perkins and Eduardo Perez, he came back discovered Nefario. Dr Nefario then was so very very surprised that he's not dead. Mocker told him the story to him. He then showed him robotic minions which is Gru's Minions as well Mocker then planned to attack them and the robotic minions chased them so Nefario and Gru ran and went back to the lair. Gru was so worried and mad that all of his minions were gone. Nefario then thinked about it when they felt pokes and familiar voices. It was 3 of the minions Dave, Phil and Carl. They're so happy that they at least have minions left. Mocker was once again defeated but not yet dead as well.