In honor of Zelda's 25th anniversary, Mario pays homage.
http://www.nintendoworldreport.com/news/26642
A level designed to look like a 2D Zelda dungeon was shown at the E3 2011 developer presentation.
Done for the Zelda 25th anniversary, the level features a lot of Zelda references, including the very look of the level and the puzzles, one of which involves using the Fire Flower to light torches.
