A shirtless madman doused a stranger with a scalding liquid in an unprovoked attack in Midtown last week, disturbing new video shows. 

The 57-year-old victim was walking home on the southwest corner of West 47th Street and Sixth Avenue just after 10 p.m. July 5 when the suspect suddenly ran up to him and threw the unspecified substance at his back, according to the clip released early Monday. 

The victim briefly turned around before falling backwards onto the ground.

The suspect, who wore black shorts, said nothing during the sick assault and quickly fled. 

The victim took himself to Columbia University Irving Medical Center the next day, and was treated for second-degree burns on his back. 

Cops say the suspect is about 5 feet 7 and130 pounds, with brown hair and brown eyes.