They have entertained and amazed crowds throughout the Sochi Paralympic Winter Games with their speed and daring. They have also horrified watchers with brutal accidents that decimated the men's and women's downhill and Super-G races and resulted in Americans Tyler Walker, Alana Nichols and Stephani Victor being airlifted to hospital, the latter two teammates crashing within 10 minutes of each other.
So what makes a sit-skier tick? Paralympic skiing has three categories: vision-impaired, standing and those who have limited use of their lower bodies through causes such as cerebral palsy, paraplegia and double limb loss, who sit in a contraption which is supposedly affectionately known as a "tub". In basic terms, it is a seat attached to a single ski by a motorbike shock absorber.
In the speed events of downhill and Super-G, they can travel at speeds of up to 120km/h. The course - Sochi's Rosa Khutor - was in poor condition earlier in the week because of warm weather. Add to that bumps and jumps that can send them spiralling out of control. The risks are less in the technical events of slalom and giant slalom because the speeds are not as great, but accidents still happen because of the difficulty of manoeuvring the machines.
The racers, some of whom have spinal cord injuries, steer the machines simply through core and upper body strength, steering by leaning their weight and using hand-held outriggers.
It is easy to understand why they are regarded as the most daring - perhaps even the craziest - skiers on the slopes.
"Am I crazy - sometimes. Am I crazy on the hill - no," says Canadian sit-skier Josh Dueck, who won the downhill silver last weekend.
"It's very calculated. I don't like to take any more risks than necessary.
"I understand the risks are very real for all of us when we're pushing the limit and pushing the line. Sometimes you go down and sometimes it's not good and we're aware of that but I definitely value attrition.
"I want to be here for a long time. I want to minimise the consequences I experience in my time as a ski racer.
"So am I crazy on the track? I don't think so man, I don't think so."
Calculated risk seems to be the key to these competitors.
"For sure, from an outside perspective looking in it definitely looks wild, and out of control and borderline psychotic," says Dueck, a former aerial freestyler who broke his neck during a jump.
"I see some of the guys going down the hill and I'm like 'holy crap man, what are you thinking?' But I think there's a group of us who are pushing the limits right now who are very calculated and you've got to have a plan.
"I've got a really good support network of people, coaches and support staff who help me make decisions when I'm planning my run.
"You create a plan and you trust that plan and sometimes it gets pretty hairy.
"Coming down Lake Jump (on the slopes of Rosa Khutor), it's steep, it's borderline skydiving when your coming down a 300 to 400 metre pitch and your going from maybe 80 to 90km/h to 120 and you're just hair back and youre holding on.
"It's too fast to be thinking so you have to have a plan and you have to trust it. You have to know this is where I need to make this move.
"If you don' have a plan you're stupid; the risks will add up in a hurry."
Even in the best-made preparation, things can easily go wrong when they ski on the edge.
"Ninety-nine percent of the time I know what I am doing," says Austria's dual Sochi medallist Claudia Loesch, who crashed out badly in the opening day downhill race.
"I know what I'm risking and I know that it's dangerous what we do sometimes but on the other hand I'm not risking it because I'm tired of living or anything, it's fun for me."
However, most admit they do possess some degree of adrenalin chasing.
"Many of us are here are in this situation because we took risks and it went wrong," Britain's Anna Turney says.
"There is risk and you have to be open-minded about that and I guess you have to accept that and you've got to like the speed and the excitement and the adrenalin and the feeling.
"It feels great when it goes well. It's really liberating, it's really exciting."
Australia's Tori Pendergast, who is competing in the technical events at her first Paralympic Games, says the desire to put it all on the line comes from an even deeper place.
"It just gives me a sense of freedom doing what everyone else does and knowing that I can ski next to a person who has full mobility and full ability and I can easily just beat them down the hill or ski next to them without having to cause any issues," Pendergast says.
Many have had accidents but they do their best to put aside the pictures of tumbling bodies and their concern for the skier, who in such a small community is often as much of a friend as a rival.
"It definitely hits home about how dangerous this sport can be and how fast we can actually go in these mono-skis and just one tiny mistake that you don't really expect can just throw yourself completely out," Pendergast says.
"It's scary and kind of shocking at the same time but its part of what we do. There's always going to be an element of danger ... it's sometimes just a matter of can we make it down in the end."
And for Super-G bronze medallst Caleb Brousseau that is what really matters.
"If I'm more scared then the first day I started, I won't go down it, so if I feel too scared at the top of the course I'll say 'coach, I don't think this is safe'."
"I haven't had it yet."