Metro

Nightmare HS stabbing

A 15-year-old boy was stabbed in the head yesterday by a scissors-wielding classmate after the pair got into a fight over a basketball at Brooklyn’s famed former Erasmus HS, authorities said.

The victim, Alfredo Allen — who attends the HS for Youth and Community Development at what is now the Erasmus Hall Campus on Flatbush Avenue — was clinging to life, sources said.

“When he fell, I saw the blood all over the floor. I thought he was dead,” said a shaken witness, Kimberly Davis, 15.

Allen’s alleged attacker, Chevoy Nelson — a 16-year-old student at the HS for Service & Learning, which is also housed on the site — plunged the scissors into his skull and neck between four and seven times at around 12:30 p.m. as shocked witnesses watched in horror, authorities said.

Nelson was arrested, and charges were pending.

The teens had been shooting hoops during lunchtime in a gym shared by the separate high schools when the fight broke out, students said.

Nelson allegedly shoved Allen as the pair fought over a basketball, and Allen retaliated by punching him in the face, witnesses said.

Nelson ran off the court and into a classroom, where he asked a teacher for acid, a police source said. The teacher scoffed, but as she turned around, Nelson grabbed a pair of scissors and ran back into the gym, a source said.

The violence is a far cry from the glory days of Erasmus, whose graduates include singers Neil Diamond and Barbara Streisand.

Additional reporting by Larry Celona and Kirstan Conley