Super Mario: Gate of Dreams
I've not gotten too far with planning, but you'll be accessing Mario's dreams and subconsciousness (is that even a word lol). Also probably a world based off Portal (by that I mean the test chambers aspect, no portals involved). Maybe a certain GFX request I made a while ago will play a role. And there'll be an invasion of Mario's worst enemy later in the game. It's even more dangerous then Metapod. It is... well, you'll wait for me starting the episode to know it
(And a shrinking mechanic probably)
I came up with the name 10 seconds ago and stole it from a Mario Kart Wii Custom Track.
Don't sue me SpyKid