Superman, quit horsing around!

A costumed protester dressed as the Man of Steel mounted the George Washington statue in Union Square Park yesterday and launched into a series of bizarre rants, authorities said.

Maksim Katsnelson, who has engaged in public outbursts before, climbed the bronze steed and sat on the saddle alongside America’s first president for about 45 minutes, cops and witnesses said.

When Katsnelson, 25, finally agreed to get down, he was strapped to a gurney and taken to Beth Israel Hospital for psychiatric evaluation.

He will not be charged, cops said.