#1 Brock Lesnar was part of an altercation with Chris Jericho back in 2016
Brock Lesnar was booked to defeat Randy Orton in the main event of SummerSlam back in 2016, but it wasn't as well-known backstage that the win would be by TKO. Elbows to the head of Orton busted the star open and left him in a pool of his own blood to close out the pay-per-view.
Backstage, Chris Jericho was watching the show and asked officials if Lesnar was working a shoot on Orton or if this was the plan since Orton legitimately suffered a concussion that night.
When he wasn't told that it was a work by producer Michael Hayes, Chris Jericho was freely calling the finish to the match "bulls**t" whilst in gorilla position which annoyed Lesnar as he came through the curtain.
The Beast told Jericho that it was none of his business but Y2J continued to ask questions which resulted in Lesnar shoving him out of the way. Jericho then went face to face with the Champion which was when Lesnar kissed him on the forehead and said "kiss me p***y" which then saw Y2J prepare to fight Lesnar before the two men were split up.
Vince McMahon and Triple H were the ones who broke up the fight with the two men ushering Lesnar away.