There have been thousands of penalties called in the NFL over the past 15 years, but until Thursday night, there was one penalty that had NEVER been called in that span: Illegal forward handing. 

During the first half of the Bears' game against the Patriots, Chicago got flagged for that exact penalty. If you don't know what "illegal forward handing: is, don't worry, most people don't, and that's because it almost never gets called. 

On the play, Caleb Williams took the snap and immediately handed the ball off to guard Joe Thuney. This was a trick play by the Bears and not only did it NOT work, but they lost five yards after the officiating crew threw a flag. 

The reason you don't see offensive linemen get more handoffs is because in most instances, it's against the rules. As the NFL rule book clearly states, "except where permitted by rule, handing the ball forward to a teammate is illegal."

So what exactly does that mean? 

• It is legal to make a forward handoff behind the line of scrimmage, but only to a player who's eligible to have the ball, such as a running back or a receiver. Giving the ball to an offensive lineman is legal, but only if it's a normal backward handoff.  
• Once the ball passes the line of scrimmage, you can't have a forward handoff under any circumstances to any player. 
• You also aren't allowed to have a forward handoff after a change of possession. So if a player intercepts a pass, he can't turn around and make a forward handoff to a teammate.

Although you can't have a forward handoff in those last two situations, you can have a backward handoff or pitch it backwards to a teammate once your past the line of scrimmage or after a turnover. 

The penalty on Thursday night marked the first time in 16 years that an illegal forward handoff has been called in a game. According to NFLpenalties.com, the last time this flag was thrown came in a Packers-Lions game on Oct. 3, 2010. In that game, Lions cornerback Chris Houston picked off Aaron Rodgers and then got flagged after he attempted to hand the ball to a teammate who was in front of him. 

This is one of the rarest penalties in the NFL and we all got to witness it on Thursday night.