Allegedly, Brock Lesnar and Vince McMahon were involved in a heated exchange on Sunday night but no one seems to know the whole story.

While the main event of WrestleMania 34 wasn't exactly the blockbuster match that Vince McMahon likely envisioned it being, it did have a shock ending. Fans had assumed for a full year that the main event of this year's WrestleMania would be Brock Lesnar vs Roman Reigns with The Big Dog winning the Universal Title and The Beast Incarnate walking off into the sunset, or more specifically into the octagon.

That didn't happen of course and even though WrestleMania 34 has been and gone Lesnar is still Universal Champion. The former UFC Champion kept his title by delivering six F5s to his opponent and controversially leaving him in a pool of his own blood. Despite picking up the win, it has been reported that Lesnar was not happy after the match and got into an argument with Mr. McMahon once he got backstage.

NEXT: BROCK LESNAR AND MCMAHON HAVE HEATED EXCHANGE AFTER WRESTLEMANIA

via wwe.com

Ryan Satin of Pro Wrestling Sheet reported on Monday that Lesnar and McMahon clashed backstage and that even though the argument did not get physical, The Beast threw his Universal Title at the wall. It has also been reported by The Wrestling Observer that Shane McMahon got between the two of them and actually squared up to Lesnar.

What caused these two massive personalities to get heated and clash though is anyone's guess. Lesnar may have angered McMahon by busting Reigns open or perhaps the two are engaged in a contract dispute. We now know that Lesnar will be around until at least April 27, 2018, when he will travel to Saudi Arabia with WWE and defend his title against Reigns once again at The Greatest Royal Rumble inside a steel cage.

The reason behind why Lesnar and McMahon clashed may be one of those mysteries we never find out the whole truth about. If it was about the blood then it wouldn't be the first time Lesnar has clashed with someone backstage over making his opponent bleed. After SummerSlam in 2016, Chris Jericho had some choice words for Lesnar after he left Randy Orton in a pool of his own blood in a very similar situation to what he did to Reigns at WrestleMania.

NEXT: SHANE MCMAHON INVOLVED IN VINCE AND LESNAR ALTERCATION