A rock band’s lead singer got a little too hardcore during a live show — pulling down her pants and taking a major leak on a dude’s face … who seemed to be all about it.

This wild incident went down Thursday night during the Welcome to Rockville festival at the Daytona International Speedway — where Brass Against performed to a ton of fanfare … and eventually, to a ton of grossed-out spectators who witnessed this unsanitary scene.

Frontwoman Sophia Urista was rocking out during their set — and performing a cover Rage Against the Machine’s “Wake Up” — when she and the band apparently invited a guy in the front row to come on up and receive a golden shower … to which he happily obliged.

Unclear exactly if he knew what he was in for — but he seemed more than willing to lie down on stage (with a can mounted to his forehead) and let Urista do her thing.

That thing, as it turned out, was to wiz all over his head and body … and it was captured in graphic detail from folks who were no more than 15 or 20 feet away. She unbuttoned her pants, pulled down her panties and then got into a squat position and hovered.

Soon, the live stream started … and she let it rip for a good 10 seconds or so. The downpour of urine absolutely buried the man’s face — and he even spits some out which came shooting up looking like a spray of water. Yeah, it’s freaking gnarly … and gross as hell.

You can go find the video for yourself online — we can’t really post it here because, well … it’s just a little too vile to depict in full. But, trust when we say — it’s quite a sight.

Brass Against has since apologized for the stunt — on behalf of Urista too, it seems — taking to Twitter to write, “We had a great time last night at Welcome to Rockville,” Brass Against tweeted. “Sophia got carried away. That’s not something the rest of us expected, and it’s not something you’ll see again at our shows. Thanks for bringing it last night, Daytona.”

Watch video below (Please confirm that you are of age):