The alleged Brooklyn serial slasher charged with killing a beloved lottery winner during a string of unprovoked assaults last weekend also unleashed his rage on an NYPD cop watching over him at the hospital, prosecutors said.

Joevani Vale — the 26-year-old who led police on a manhunt after allegedly fatally stabbing Ramon Cintron, 83, in a Brooklyn housing project — attacked the officer inside Maimonides Medical Center Wednesday night, according to a criminal complaint against him unsealed Friday.

Vale allegedly sucker-punched the officer in the face “with a closed fist” around 11:45 p.m. while the cop was escorting him to the bathroom, the complaint says.

“Where are we going,” Vale reportedly asked the officer before throwing the punch.

The cop was left with pain and redness and was left “annoyed,” the document states.

The bizarre attack earned Vale five additional charges stacked on top of his murder and assault charges.

He was arrested Monday shortly after walking into the Brooklyn hospital with no visible injuries, though sources said he appeared to be high.

He is accused of attacking three different people in a one-hour slashing spree in Brooklyn Saturday.

He allegedly punched a 47-year-old woman and slashed a 31-year-old woman before following Cintron into the elevator at the Wyckoff Houses public housing complex and brutally attacking the elderly man.

Cintron was declared dead at the scene.

Vale was arraigned Friday and remanded.