No two people are the same—not in life, and certainly not in the Ultimate Fighting Championship.
The UFC is home to nearly every appearance a mind can imagine, which includes but is not limited to the nice guys, the fighters who keep to themselves and, of course, the mean ones.
Simply taking a look at many of these fighters will send the hairs on your neck straight up in the air.
Whether these specific fighters have a mean personality doesn't matter, as they are downright mean-looking.
The following slides display the 20 meanest-looking fighters in the UFC.
I think Thiago Alves' nickname of the "Pitbull" pretty much sums it up.
Chris Leben is one of the most-liked fighters in the UFC today.
However, Leben's craziness mixed with a pinch of mean has allowed him to become one of the meanest mugs in the UFC.
Overall, Nick Diaz isn't a mean guy as much as he lets the media believe.
But Diaz demonstrated just how mean he can look in his staredown with BJ Penn at UFC 137.
Diego Sanchez may be small, but he's arguably the meanest-looking guy in the business.
Wanderlei Silva is home to a nickname that often makes fans wonder where he got it from.
"The Axe Murderer."
We can only hope.
There are few fighters who have a meaner appearance than Brock Lesnar.
While Lesnar is a gentle man at heart, his looks make us think otherwise.
When the rubber meets the road, Nate Diaz is still a Diaz.
While stupidity may come to conquer at times, his mean appeal is hard to forget.
Josh Neer certainly isn't one of the more well-known fighters in the UFC today, but he is one of the meanest-looking.
Pat Barry? Seriously?
We all know that at times Pat Barry can be one of the funniest fighters in the UFC.
But there's also another side of Barry that's fairly mean.
Have you ever seen Paulo Thiago smile?
Good—now I don't feel alone.
Depending on the day, Clay Guida can be smiling, bleeding or looking nice and mean.
If you caught his staredown with Diego Sanchez, you'll know what I mean.
The Huntington Beach Bad Boy may not be too bad anymore, but he remains mean-looking.
That's something no one will ever be able to take away from Tito Ortiz.
If "Rampage" has the grill in, he's not too scary to look at.
But when Jackson has the chains around his neck, well, he's frightening to look at.
It's rare that Cheick Kongo ever says a word.
Maybe that's what makes him even scarier.
It's fair to say Kongo is one of the meanest-looking guys in the organization.
Alistair Overeem is taking his talents to the UFC, and he's bringing his mean appearance with him.
Here come the chills again.
Maybe it's because he's a former heavyweight champion, or maybe it's because he's Cain Velasquez.
Either way, Velasquez is one mean-looking dude.
While Melvin Guillard may not always deliver when it matters, he still has the mean looks, right?
Guillard may smile a lot, but don't let that fool you.
Sweet mercy, Shane Carwin is mean-looking.
The world-class knockout power is just an add-on bonus.
We all know that Mauricio "Shogun" Rua is a very likable fighter.
Point proven that looks can be deceiving.
Mean to the bone.
Be afraid—be very afraid.
Thiago Silva may be missing from action as of late, but he remains one of the meanest fighters in the UFC today.
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