You had one job, Bryan Tanaka.
During the launch of her Las Vegas residency, "The Butterfly Returns," Mariah Carey took a slight spill ... but magically her voice continued to boom throughout the Caesars Palace Colosseum.
While belting out her lyrics, Carey was helped onto a rolling box by BF Tanaka, but he didn't provide enough counter-weight on the back and the diva tipped over.
Even though the microphone was taken away from her mouth, the track continued to play as if nothing had happened.
She was able to shake off the flub and continue on with the performance, but there's a good chance Tanaka is in the doghouse.