Seeing as the WWE and Jackass have a lot in common, it doesn't surprise us that they have a shared history.
In 2007, Johnny Knoxville and the rest of the gang were supposed to invade SummerSlam; however, the deal fell apart once the Jackass gang dropped out of the affair. There were various reports regarding the group's departure, but Johnny later revealed to JackassWorld.com (via PWInsider) that plans had sadly fallen through.
At the time, WWE wanted more than one night's worth of commitment; unfortunately, Johnny couldn't fit that into his schedule. As a result, WWE moved in a different direction, but it's clear there was no bad blood since Johnny returned to the scene in 2008 on an episode of Monday Night Raw.
After messing with The Great Khali throughout 2008 in a series of videos, Johnny eventually faced the consequences on Raw. Once he entered the ring, Johnny immediately encountered the beating of a lifetime from Beth Phoenix, Hornswoggle, The Boogeyman, and The Great Khali. According to Bleacher Report, Johnny told people backstage that the infamous "Khali Bomb" rendered him unconscious for a few seconds.