A man bit another man's lip off during a fight in a Brooklyn subway station over the weekend.

A police spokesperson said the incident happened around 10 p.m. on Saturday night at the Crown Heights-Utica Avenue subway station in Crown Heights. The victim was punched in the head by the unknown suspect after a fight broke out between the two men, according to the spokesperson. During the altercation, the suspect bit the victim on the lip and jaw, removing a piece of his lip and causing serious injury.

The victim was taken to Kings County Hospital in serious condition. The assailant is still at large, and the investigation is ongoing.

Video of the fight was uploaded online—it's NSFW but you can watch it below. It's unclear what caused the fight—the video uploader just writes, "Argument in the subway turns to a fistfight. During the struggle, one bit the others lip off." But you can see people gather around as the two men circle each other, then begin brawling.