A 12-year-old girl was arrested and charged with assault on Thursday after a bizarre attack at a sleepover party in the Bronx that left an 11-year-old girl with second-degree burns to her face and upper body.

The victim, Jamoneisha Merritt, was sleeping on a living-room couch, the police said, when the 12-year-old poured a cup of boiling water over her face and shoulders. Friends inside the apartment then poured cold water on the scalded girl to try to alleviate the pain, according to the police.

Police officers responding to a 911 call at 4:40 a.m. on Monday arrived at the apartment at 1064 Findlay Avenue to find Jamoneisha, who lives in a neighboring building, conscious, with burns on her face, neck, chest and back.

She was taken to Harlem Hospital, where she remained in serious but stable condition, her mother, Ebony Merritt, said.