FILE UNDER: "This guy's never gonna live this down."

Unbeknownst to the Tool fan attending Monday night's (October 21st) concert at L.A.'s Staples Center, the dude he asked to get a cool shot of him posed in front of the stage was, actually EDDIE VAN HALEN.

Wolfgang Van Halen was quick on the draw and took a pretty hysterical photo of his dad doing the guy a solid and taking the photo.

Wolfgang posted the photo on Instagram, writing, "A guy asked my dad if he could take a picture of him with the stage behind him, having no idea who he just asked, and that was my favorite moment from the Tool show last night."