A 25-year-old man has been arrested on suspicion of GBH after someone was bitten on the face in a nightclub in Oxford.
The victim, a 36-year-old man, required surgery after the attack at The Bridge club in Hythe Bridge Street on Saturday at about 02:20 BST.
Thames Valley Police has released a CCTV image of someone who might have witnessed the incident.
The suspect, from Abingdon, has been released under investigation.
Det Con James Macaro said: "If you are the man in the image or if you know who he is please contact police as soon as possible."