Brady once peed on Matt Cassel's practice jersey during prank war

Tom Brady apparently takes pranks very seriously.

On "Patriots Pregame Live" during Monday Night Football, former New England Patriots quarterback Matt Cassel spoke about a prank war he engaged in with Brady during his second NFL season - one that got pretty ruthless.

"I was coming in and a prank war started where he knocked my tray out of my hand, he put his foot up against the door, I poured some protein shake in his shoes, maybe some flexi-hot into his underwear," Cassel said, according to Michael DePrisco of NBC Sports Boston. "He dumped a trash can on my car and then decided to pee on my practice jersey, and then he asked me to forgive him and call him Captain Longshanks.

"So I was like, 'No I'm not doing that, I'm going to do something even worse to you,' and by the time we came in for practice, I had three tires (from my car) in front of my locker, the other one was hidden, you know the old 'Put in on the blocks.' The old adage goes back to don't mess with people that have more money than you do."

The prank war came to an end after head coach Bill Belichick stopped it.

"Bill had to step in and say, 'Look, guys, this isn't World War 4, okay," Cassel said. "We can't have you guys going around hurting somebody or killing somebody.'"

Cassel served as Brady's backup in New England from 2005-07 before taking over starting duties when the latter suffered a torn ACL and MCL in the 2008 season opener.