An ugly moment was caught on camera at a high school football field in Linden, New Jersey.
A player is seen ripping off the helmet of an opponent and then hitting him in the head with it during a play.
The opponent left the game with a head injury - getting 10 stitches. The other player remained in the game.
The shocking incident happened last Friday and the video has since gone viral on the internet.
Officials said they didn't realize the severity of it until they went back and watched the video.
The school system is now investigating.