What it tests: Fear of small spaces and upper-body strength
Why it’s harder than it seems: In this obstacle, you crawl downhill through a black tube into freezing water, then uphill out the other side. You anticipate the tight, claustrophobia-inducing space, but as you inch your way higher, a steep incline awaits. “The angle of exit makes pushing your way through very difficult,” says Kombol. An extra push of upper body strength will get you though—as long as you don’t lose it first.
Completion Rate: Kombol estimates that only 40% are able to make it out without any help.