Super Mario Infinity 2: The Cursed Gem/Goals/Rocky Ruins
From SMWiki
Rocky Ruins 2 Secret Exit
NEED: Hint from Lemmy's Castle
Follow the hint you received in Lemmy's Castle (see below) to find the secret exit in this level.
#6 Lemmy's Castle Hint
Going behind Lemmy's Castle (to the right of the blocked pipe) will bring you to an area with a Message Block that will tell you how to find the secret exit in Rocky Ruins 2. You can exit this level from the side, as the coin arrow indicates.
Ruins Secret Secret Exit
Use the block to jump through the hole in the ceiling above the vine in the area containing the flying obstacle course. Defeat all the enemies in this room for the key and keyhole to appear.

