#4 Rob Gronkowski turns heel and attacks Mojo Rawley
Thus far, Rob Gronkowski and Mojo Rawley have been as thick as thieves, but one has to admit that there's something about The Gronk that just screams heel. While I may be guessing here, I'm pretty sure that had he made his debut in front of a packed crowd, he would have gotten booed.
So, the WrestleMania host could show up on the ramp at WrestleMania and invite his best friend Mojo Rawley to join him, in celebrating the grand event. And as the two men get hyped, Gronkowski could attack Mojo Rawley and firmly attest to something that we've known from the moment we first laid sight on him- he is not a very good guy.
Rob Gronkowski could go on to become the same sort of bad guy that King Corbin is, where there's a massive amount of heat on him from the moment that he steps into the arena. It even allows for Mojo Rawley to have a mini feud, as a babyface.