An 8-year-old boy was punched in the head by a violent stranger with “blotchy” skin and an injured eye inside a Financial District train station, police said Tuesday.

The Brooklyn boy was standing with his mother inside a waiting train at Fulton Street station near William Street around 8:40 p.m. Monday when the stranger approached.

Without uttering a word, he punched the child in the back of the head before fleeing, police said.

The victim was taken to NewYork-Presbyterian Lower Manhattan Hospital, where he was treated and released.

Police describe the attacker as approximately 50 years old, 6 feet 2 and 200 pounds. Cops also said he has a “blotchy complexion, an injured right eye, a salt and pepper beard and hair.”