#6 - Jens "Lil Evil" Pulver

Let me guess, you chose that one because "Lil Bow Wow" was already taken?
#5 - Marcus "The Irish Hand Grenade" Davis

I don't care how deadly an Irish Hand Grenade may be, Marcus Davis. It's still a crummy nickname.
#4 - Kristian "The Weather Underground" Rothaermel

Isn't "The Weather Underground" also a local weather news site? Perhaps Kristian just struck a good enough advertising deal with the company to be able to endure such a terrible nickname.
#3 - Allen "Monstah Lobstah" Berube

He gets points for originality, but "Monstah Lobstah"'s cheesiness still requires no explanation.
#2 - Cheick "The French Sensation" Kongo

"The French Sensation" sounds like an excellent nickname if you're about to delve into the porn industry. But when you're rolling around on the floor while wrestling with a bunch of dudes, it becomes less appropriate.
#1 - Tito "The Huntington Beach Bad Boy" Ortiz

C'mon, this is like being from Los Angeles county and calling yourself the Malibu Beach Bad Boy. All you have to do to be considered rebellious along the Orange County coast line is to prefer to skateboard instead of surf.