Styles met with McMahon inside his office on Tuesday right before Smackdown went off the air.
McMahon immediately tried to get under Styles' skin, stating that they are a lot alike as they both have black holes inside their hearts. McMahon slapped The Phenomenal One saying he wanted to see the animal inside of him come out.
Styles then lost his temper and punched McMahon in the face, sending the WWE boss to the floor. WWE officials quickly rushed in to remove Styles from the office and to check on McMahon who was smiling.
Also on Smackdown, Shinsuke Nakamura defended his United States Championship against Rusev in the main event of the night.
The hard-hitting bout appeared to be over after Rusev stopped Nakamura from unleashing his Kinshasa with a Machka Kick which nearly won him the match.
Rusev would later withstand a knee to the face by Nakamura to deliver a second Machka Kick to win the match and become the new United States Champion. Rusev's wife Lana celebrated from ringside.
Other moments from Smackdown included Mustafa Ali defeating Andrade 'Cien' Almas before he was attacked backstage by WWE Champion Daniel Bryan; The Usos and Gallows and Anderson defeating The Bar and Sanity; Shane McMahon finally agreeing to become The Miz's tag team partner during a segment of Miz TV; Samoa Joe defeating Jess Hardy via disqualification; and Bryan attacking R-Truth who was dressed up as Santa Claus.
Bryan put an end to Truth's holiday celebration with Carmella stating that the material items bought during Christmas is ruining the planet. R-Truth responded by calling Bryan an angry elf and threatened to defeat Bryan for his WWE Championship after he wins the Royal Rumble. Bryan then assaulted Truth and locked in his Heel Hook submission hold.