Magic Cape
This mystical cape is found in A Link to the Past under one of the graves. Upon donning it, Link becomes invisible, being able to pass through enemies and barriers at will. This comes at a high price though, as the cape demands a high amount of magic energy to sustain. The only way you can get into the cave is by performing a dash attack into the grave surrounded by dark colored rocks (the ones which can only be lifted using the Titan's Mitt) in the Graveyard.
The Magic Cape is necessary to gain access to one Piece of Heart by walking through a bumper on Death Mountain.