1. Santino Marella
WWE.comIt was the most memorable debut in WWE history as Raw took place in Milan, Italy on the April 16, 2007 edition of Raw. Vince McMahon was a heel that was supporting Umaga and he was in the ring issuing an open challenge to anybody that wanted to face Umaga in a match for the Intercontinental Title. Nobody from the back came out to challenge him, so McMahon said somebody from the crowd could face him. There were a number of fans that wanted to face Umaga, so McMahon focused on this regular looking guy in a brown shirt that was sitting in the first row. We had no idea who he was. He was a mystery to the viewers at home. When McMahon asked him his name he said: "Santino Marella." The crowd erupted in cheers for him. They were strongly behind him. McMahon also made fun of his wardrobe including the brown shirt and the red shoes.
https://www.youtube.com/watch?v=pGju3Wl34QU As the IC Title match started, Santino actually got some offense in with some kicks and a rollup, but then McMahon announced it was a No Holds Barred Match. Umaga dominated the action with his great power moves as it looked like poor Santino had no chance to do anything in this match. Then the crowd erupted as Bobby Lashley ran down to the ring. He slammed Umaga, then grabbed a chair from McMahon and crushed Umaga with a chair shot to the head. Lashley hit a Spear. Then Lashley put Santino on top and that led to Santino winning the IC Title. It was a great angle and one of the most debuts of any wrestler ever. Santino made a splash as a regular fan that became the IC Champion and then a WWE contracted wrestler as well.