Christina Aguilera has sparked another stage mishap debate. The singer -- who is still being criticized for her flawed rendition of The Star-Spangled Banner at the 2011 Super Bowl -- was seen wiping her leg while paying tribute to Etta James at the late singer's funeral.

Aguilera, ever the professional, kept her cool and stayed right where she was. She then proceeded to sing a fantastic rendition of James' famous song At Last.

But now fans want to know: Was she wiping away a dripping spray tan, or something more organic?

Aguilera is not the only artist to have an onstage problem, although she's one of the few who kept it professional. Here are five other stage incidents -- some of them quite nasty -- and the celebs who either kept their cool and kept on going, or didn't.

Fergie

The Black Eyed Peas singer admitted to answering nature's call onstage. Hey, when you gotta go, you gotta go.

Beyonce

Beyonce has taken many a spill while performing onstage, mostly thanks to unsafe costume choices. And what does she do? She gets right back up and keeps on going. She talked about falling down a flight of onstage stairs while performing in Florida -- she even hit her chin -- in an interview with CNN: Whenever I do something like that I always perform really, really hard because it makes me a little mad at myself so I just go crazy.

Mariah Carey

Carey is known for being a stage diva, and she seems to relish the title. She messed up the first line to one of her songs at a Toronto concert and did the most natural thing that came to her: she stopped performing and complained about a hole on the stage (Just about the size of a stiletto heel) and had the stage people come and fix it. She swore she wasn't complaining because of her own mishap, but still, it wasn't her classiest moment.

Steven Tyler

The show couldn't go on when Aerosmith frontman Steven Tyler fell offstage in 2009 after doing a bizarre, high-energy dance. He lost his balance and fell into the crowd. The singer, who was 61 years old at the time, told Rolling Stone that he ended up breaking his shoulder.

Gene Simmons

The flame-breathing Kiss member accidentally set himself on fire while performing his famous gimmick. He was immediately helped on stage by someone who put out the fire.