One of the punks arrested for allegedly pelting NYPD cops with snowballs during a raucous melee in Washington Square Park was arrested weeks ago for trying to rob a confused subway rider in what he claimed was a social media prank.

Gusmane Coulibaly, 27, is seen intimidating a stranger and trying to shake him down for cash inside a Bronx subway station on Feb. 6, according to a resurfaced video posted on his YouTube channel — where he goes by the name “Diaperman.”

The stranger bolted towards the emergency exit, where he tried to seek help from a man in a reflector jacket he mistook for MTA police.

“So you gonna pay up?” Coulibaly asked the stranger, the video shows.

“Pay up what?” the other man said.

“My bread, n–ga,” Coulibaly persisted.

“How much you got? Whatever you wanna give, n–-a. F–k me, n–a, I’ve been looking for you for a week straight,” he continued.

“I don’t even know you,” the frazzled man retorted as he picked up his things and tried to flee.

“If I get mad, I’m gonna have to run your pockets, bro. Gangsta,” Coulibaly threatened.

In a last-ditch effort to escape the bizarre situation, the man claimed he was a cop, then approached two men who turned out to be actual police officers.