Before Deadmau5 and Foo Fighters joined forces Sunday night at the 54th Annual Grammy Awards, the Canadian superstar DJ made some news of his own by playing a joke on his DJ pal Skrillex on the red carpet.

It began when Deadmau5 arrived on the red carpet wearing (n addition to his trademark mouse helmet) a black t-shirt with a phone number and the phrase “U mad bro?"

Deadmau5 and Rihanna were among the acts last night at the House of Blues in L.A., where a major fundraiser was held for Children's Hospital Los Angeles.

Those curious enough to call the number would have reached his fellow nominee Skrillex. Or, more likely, his voice mail.

(Lifeline Live) Electronic artist and mouse head helmet wearer Deadmau5 pulled quit a nice little prank on dubstep king Skrillex at the Grammys last night. He tweeted a picture of himself on the red carpet with the text, “Maximum trolling achieved.