According to James Sroden, the popular Blue Man Group attacked him when he went to see their show in October 2006. He says they forced him on stage, circled him, held his neck and arms, forced his head back, and then inserted an "esophagus cam" down his throat, projecting an image of his throat onto a large screen.
Sroden says he subsequently bled from the nose, had nightmares, and lost fillings in his teeth.
The Blue Man Group's version of events is quite different. From msnbc.com
The Blue Man Group's Chicago general manager said the stunt is just an illusion.
"Essentially, we have a piece in the show where an actor holds a camera to an audience member's mouth, doesn't enter their mouth, and then we play a video," Kori Prior said. "We have been performing this show in this theater for 10 years and have never had this issue before."
So it seems that Sroden is expecting a jury to believe that the Blue Man Group's illusion is actually real. Maybe he's hoping the Blue Man Group will pay him something in order to avoid going to court. (Thanks, William)