Steve-O Terrifyingly Ollies Over UFC's Jon Jones In Awesome Skate Park Sesh

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 ... Steve-O can REALLY skate -- and Jon even tried his hand at going up and down a ramp a few times, too!!!

By the way, Steve-O tells us he was scared out of his mind to let Jon on the board, saying, "a wave of panic swept over me for the possibility that I might be responsible for the career-ending injury of the greatest mixed martial artist of all time."

But -- both dudes ended the sesh OK ... and Steve-O added, "so glad we got away with it!"

Us too!!!

By the way, if you're wondering why the duo are spending time together in New Mexico ... it's all for a great cause.

Steve-O joined the UFC champ to help his efforts with the C.A.R.E. project ... raising money and support for communities impacted by the COVID-19 pandemic in New Mexico.