A creep in a Halloween mask attacked a random pedestrian with an ax on the Upper West Side this week, cops said Tuesday.

The 51-year-old victim was on Broadway near West 61st Street just after 10 p.m. Monday when the suspect — shown in one photo wearing the toothy mask over his face — threatened to kill him and struck his arm with the ax without provocation, cops said. 

The suspect then bolted into the 59th Street/Columbus Circle subway station.

He is shown in another photo sans the getup and wearing a blue surgical mask. He also wore a dark-colored coat, blue jeans and black boots.

The victim was taken to Mount Sinai Morningside in stable condition, cops said.