Cane of Byrna
In Legend of Zelda: A Link to The Past, the Cane of Byrna is found in a cave on Death Mountain, south of the Tower of Hera in the Dark World. Link must already possess the Magic Cape, Magic Hammer and the Titan's Mitt to obtain this item. When used, the Cane of Byrna creates a forcefield around Link, making him invincible (take no damage from attack or spikes), and consuming magic power. The Cane of Byrna has essentially the same affect as the Magic Cape, but the difference is that the forcefield will damage enemies if they make contact with Link and the enemies can see you during it's use. Throughout the game, there is no necessity for this item, and the game may be completed without it's use.