@karkar18: It's in Cola Secret 2.
Sorry for the slow progress recently. I moved house a couple weeks ago and just got internet access on Wednesday. I was still able to get one level done in the meantime though.
COCOA SECRET 2
It's a vertical level full of Thwomps.
They don't always travel vertically either. If a Thwomp-centered level just had the vanilla Thwomps, it could get boring, right?
Of course, there are some other enemies here too.