This Super Mario Maker level is called Trials of Death, a level so tough the guy who made it has been trying for over a year to complete it.
There's a great interview up with its creator Braden "ChainChompBraden" Moor over on Waypoint. Moor has spent 1500 hours trying to beat it. Without success.
If you are reading this and wondering "huh maybe I could beat it", you are overestimating your abilities. Look at this nonsense.
Speaking with Waypoint's up-and-coming young games journalist Patrick Klepek, Moor says of people's claims that somehow, one day, Trials of Death will be cleared: "I'm always seeing people say that it's never going to happen, and that the whole thing is just hopeless."
"That's just an extra exciting reason for me to beat this level. I'll get to prove a bunch of people wrong. If this isn't an example of my stubbornness, then I don't know what is. Perhaps most motivating of all however, is that I simply enjoy this journey."