#5 Tazz
Tazz, or 'Taz' as he was at the time, was to ECW in the 90's that Brock Lesnar is to WWE today, only with actual regular wrestling appearances.
Taz was almost untouchable, he ran through everybody in ECW, from Sabu to Shane Douglas to the Dudley Boyz. He was a force to be reckoned with and the original suplex machine.
During his time with ECW, Taz was the ECW World Champion, a two-time ECW TV Champion, three-time ECW Tag Team Champion and also created his own title, the FTW Championship, which he held twice.
Then he joined WWE in 2000 and was not the same man anymore. Despite a strong and memorable debut at the Royal Rumble 2000 with a win over Kurt Angle, Tazz soon fell into the hardcore ranks and struggled to shake it off.
He did receive small pushes here and there in 2000 and 2001, but nothing compared to how he was in ECW. Ultimately he would be a 3 time WWE Hardcore Champion and a Tag Team Champion with Spike Dudley.
While a WWE superstar, Tazz returned to ECW and in a bizarre piece of professional wrestling history, ECW and WWE officials agreed to have Tazz, a WWE wrestler, make a surprise appearance at an ECW show to defeat then ECW Champion Mike Awesome, a WCW wrestler, for the ECW World Heavyweight Championship.
Tazz appeared on an episode of Smackdown with the belt, where he lost to WWE Champion Triple H, in a match designed to show WWE's already known superiority over ECW.