Got mine DH biking a while ago. I went over the bars and instantly saw static (like a blank channel on the TV), and heard the highest-pitch scream I could imagine. Nobody else was with me (which was stupid on my part), so idk if I seized or anything while I was out.
I woke up some time later, and knew both wrists were broken, but didn't notice anything with my head until I got up. I stood, and a fizzing black mass filled half of my right eye's vision. Got scared and knew I had to get down the last half of the trail to patrol.
Rode it down to patrol, and they immediately call an ambulance. They strap me to a back board. And I start hallucinating. I thought I was back up on the trail, where I had crashed, with piles of logs holding me down so I couldn't get up. I could see faces, but their voices were distant and unintelligible. I begged them to help me up, but they did nothing. This seemed to go on for hours, from the patrol station, to the ambulance, to the LifeFlight Heli, and I thought I was still on the mountain.
Shit sucks.