Event promoter Mike Porra told the Hamilton Spectator it was "the biggest trick attempted in the history of freestyle motocross."
Hours later, a video of the 26-year-old's double front flip attempt was posted online.
All did not go as planned.
Spectators at the event gasped in horror as they watched Cook violently crash into the ramp, suffering a serious spinal injury.
"Something snapped!" one man is heard shouting in the video.
[ Related: B.C. stunt biker seriously injured in Hamilton show ]
Watch Cook's terrifying crash below.
Paramedics removed Cook from the scene on a stretcher and rushed him to Hamilton General Hospital.
The next day, Cook posted a photo from his hospital bed after undergoing three hours of back surgery.
"This morning I underwent 3 hours of surgery on my back and I'll likely be in hospitalRead More »from Video: Canadian motocross rider Bruce Cook recovering after terrible crash