An illegal crackback is a penalty in Football that is called on a team when a player performs a crackback block, also known as a peelback block, on an opposing player. A crackback block is a block in which a blocker blocks a defenseless player who is running towards their own endzone from the side or back below the waist.. This penalty is called due to the high risk of injury and due to the defenseless player being very vulnerable. This penalty results in a 15 yard loss for the offending team.
Multiple injuries have occurred as a result of crackback blocks, making them considered one of the dirtiest plays in Football.