A man bit off part of a man's ear and is believed to have swallowed it.
The assault happened at The Event nightclub in West Street, Brighton, in the early hours of Saturday.
The victim, minus a small part of an ear, was taken to the Royal Sussex County Hospital, Brighton, where he received treatment before being allowed home.
A police spokesman said: "They could not find the missing ear part. It is believed the offender swallowed it."
Police are trying to trace the attacker.
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