Horrifying video of invisible fire during Indy 500 race has people questioning how it's even possible

A mind-bending video of a race car driver attempting to escape an invisible fire has left viewers baffled over what was actually happening.

We all know what fire looks like, don't we? It's bright and orange, and usually comes accompanied with clouds of smoke - but apparently there are exceptions.

Proof of this comes in the form of footage filmed in 1981, when American racing driver Rick Mears pulled up for a pit stop and suddenly leapt out of his car.

Though there didn't actually seem to be anything wrong to the naked eye, a number of other people in the pit joined Mears in running around frantically, while one even grabbed an extinguisher and pointed it towards the car.

The scene looks exactly like one that would unfold if there were a car fire - but with no flames and no smoke, it's hard to connect the dots.

Viewers have been left baffled by the scene, with one person writing: "How is this even possible? Something straight from a horror movie."

"I didn’t even spot a flame this is a real nightmare," another said.

It turns out there was a fire though - just not one we can see.

Marshalls attempted to extinguish the fire but weren't able to see it. (X)

The bizarre scene is a result of the use of methanol; an alcohol-based fuel which was being used in place of gasoline because it burned for longer while also being cheaper.

However, while the substance has its positives, it also came with a downside: methanol burns with a light blue flame which means you can't see it in the daylight.

The methanol caught fire while Mears was in the car after it began spewing from the fuel hose. It spilled into the cockpit and covered his helmet and suit, prompting Mears to try and escape the car.

In an interview with the Indianapolis Motor Speedway Museum, he recalled: "I quit breathing fortunately, but I didn’t have a breath because I was struggling to get out, and I kind of kept trying to keep my eyes closed so that it wouldn’t burn my eyes."

Rick Mears was thankfully saved from the fire. (YouTube/Indianapolis Motor Speedway Museum)

"And I got unbuckled, got the wheel loose, I don’t remember now what all the scenario was, but you know ended up working my way out," Mears continued.

At first, marshals in the area didn't realize Mears was on fire and even ended up putting themselves in danger by getting too close. As a result, the driver was left screaming for help, until he saw his dad running in his direction.

"I see my dad running around, and he comes running around the corner, and he’s the only one that really knew I was on fire because he knows me and knows I don’t move that fast for anything, so I had to be on fire," he recalled.

Thankfully, Mears' father was able to put the fire out, though Mears described the ordeal as a 'long 34 seconds'.