CHICAGO (CBS) — A man had part of his ear bitten off Thursday morning in a bizarre attack across the street from the Art Institute of Chicago.

Police said a 51-year-old man was standing on the sidewalk near Adams and Michigan around 6:45 a.m. Thursday, when another man walked up and asked him if he had a light for a cigarette.

When the victim said he didn’t, the other man punched him in the back of the head, and then bit off part of his left ear, according to police.

The suspect ran south on Michigan Avenue.

The victim was being treated at Northwestern Memorial Hospital.

No one was in custody Thursday morning. Police described the suspect as a black man in his 50s, 5-foot-8, and 140 pounds, with salt and pepper hair. He was wearing a brown coat, brown shirt, and brown pants.

Area Central detectives were investigating.