Key to My Heart - by SethBling
From the Super Mario Wiki
Key to My Heart - by SethBling is Coursebot's fourth official course in Super Mario Maker, released on April 1, 2016, and made by YouTuber SethBling. It is set in the castle theme and in the Super Mario World game style.
The level begins with many Skewers to avoid. Afterwards, a Key and a Key Door appears, followed by a segment with Pink Coins and Chain Chomps. The next segment gives Mario a choice of either a Checkpoint Flag or a Fire Flower, and it follows with more Skewers and a big Rocky Wrench that Mario must take out in order to progress through the next Key Door. Afterwards, Mario reaches an area with two Skewers, and must avoid some Dry Bones until some winged Galoombas appear, which he can use to get the next Key and proceed directly to the axe to clear the level.