This content is protected hahaha...looks real from here. notice how the creators used an exact replica of jackson's slam vs arona.
Bas Rutten happens to be one of those people as well. And yes, its painfully obvious Rampage knocked Arona out with his head.
He got powerfully slammed onto the back of his skull, at a high rate of speed, from somewhere around 9 feet in the air, then bounced 3 inches off the mat into rampages head, pretty ****ing obvious which one is more likely to cause damage. The clash of heads was incidental, physics make this pretty obvious. Do you honestly think that if not for the clash of heads Arona wouldn't have been out? If Morkevicious' slam on Yano can cause a KO, theres no way Rampages couldn't. http://www.youtube.com/watch?v=hJbxyrCVMPE
He would have been seriously ****ed and the punches would have finished him off, but yes, i still think the headbutt was a major contributing factor.