A substitute teacher? He’s more of a pee brain.

Shawn Charles, 41, allegedly urinated into a white plastic cup in front of a classroom full of students at PS 224 in East New York, Brooklyn, last Dec. 12.

He left the cup under the desk, where the regular teacher found it upon returning to work on Dec. 22, says an investigator’s report.

Charles denies everything but is now on the city’s “do not call” list.