Okay, so I'm going to start this thread off by showing one of two people on youtube that have successfully cleared this custom level in Super Mario Galaxy 2. I just tried to do it and got me arse handed to me.
The objective is to go through this already near-impossible stage carrying three clouds, so that at the end platform where Rosalina is, you can use them to reach the Star. But HOLY FUCK THAT IS SO IMPOSSIBLE!
If you can think of/find any other impossible gaming challenges, post them here. Because oh my god. Mario. Wow.