Summit is a stage that originated in Brawl. While its an stage dedicated to the Ice Climbers, it wasn't really in their NES game. But if they had somehow gotten a new 3D game, you'd imagine a place like this would be there.
It's a pretty simple stage until it starts sliding down the mountain in a avalanche of snow and ice.
Then it gets a little interesting as angles are much steeper than most stages are.
But the slide doesn't last forever or for long. While far from my favorite stage, I don't hate it. But I don't quite love it either.