Retro Studios has been hard at work on Metroid Prime 4 ever since development was scrapped and restarted last year, but there was a time long ago when the talented team was apparently working on a Legend of Zelda game starring Sheik, and a Super Mario game about the mischievous ghost, Boo.
According to our friends at Shinesparkers, concept art of both of these rumoured projects has now surfaced online. The links the Metroid fan site received reportedly point to an online portfolio by Sammy Hall - a former Retro Studios pre-production artist who is known for previously assisting with the Nintendo Wii titles Metroid Prime 3: Corruption and Donkey Kong Country Returns.
The artwork is said to be pre-production art from a "cancelled Zelda project" dated somewhere between 2005 and 2008, and a "cancelled Boo project" around the time of 2006 to 2007. The details about the Boo game are rather limited. Hall titled one of the sketches as "tiny stuff for tiny handheld resolutions" - which suggested the game was planned for the Nintendo DS at the time. Some Boo concept art was titled "possession powers" and Broomies" and there's also a drawing of a world map.
The Zelda project was supposedly aiming to be "ten times weirder" than the average entry. Had the game got off the ground, the story would have been set within the "bad ending" of The Legend of Zelda: Ocarina of Time, and would have explored the journey of the last Sheikah while Dark Gerudo are "giving their 100-year birth to Ganon" and the game was planned to be an action/JRPG title.
Since this article went live, the artist's profile on ArtStation has been scrubbed of Sheik-y goodness, although Unseen64 still currently has various examples of the concept art archived, so you can head over there if you're curious.