UPDATE: According to WWE.com, the Undertaker was transported to Ochsner Medical Center in New Orleans after his match with Brock Lesnar. He underwent a CT scan and other testing and was diagnosed with a severe concussion.

He was released on Monday.

The Undertaker lost to Brock Lesnar on Sunday night for the first time ever at Wrestlemania bringing his overall record to 21-1. 

No one really expected it, it was quite shocking as you can see from some of the fan reactions in the crowd.