Wanna see Steve-O ollie over the greatest MMA fighter ever???
Good ... 'cause TMZ Sports has obtained video of the former "Jackass" star boarding over Jon Jones at a New Mexico skate park this week -- and it's both awesome AND terrifying!!!
Check out the footage ... Jones laid down on a ramp and let Steve-O skate over him -- and the first attempt nearly cracked Jon's ribs, it's pretty damn scary!!
But Steve-O eventually nailed the trick ... and Jon couldn't have been happier.
There's much more in the clip .