The perpetual leftist outrage against Donald Trump has officially bottomed out.

Hundreds of protesters gathered near the Chicago River on Sunday for a synchronized mooning of Trump Tower, which was on the other side.

Video shows a few hundred people counting down before they bent over and collectively pulled down their pants.

Another video shows the group — which consists of a lot of gray hair — cheering wildly.

Strangely, the childish antics appear to have had no effect on Trump administration policy.

Bill Ayers, is that you?