Fuck, I've seen just the video for this occasion, posted here, but I didn't save the link.
A guy on a bike got t-boned by a garbage truck. It was going slow and stopped before running him over, but the sheer momentum from its mass made the cyclist go from vertical to horizontal in a split second. His head hit the pavement, the remaining 10 minutes of the video was people waiting for an ambulance to pick up his remains.
So yeah, ride without a helmet.