There's an item that I have had in the back of my head for quite a while (along with many others). It's called the crown of Quili, basically it gives Link the ability to become completely covered in spikes. He loses his sword and shield while using it, but his whole body is now a sword. It is found within a cave dungeon or something to deal with rocks as the spikes are able to break apart boulders. That's pretty much it aside from that it's a helmet with various spikes on it.

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"When the day is about to be overcome,
And the night is about to cover across the land.
I, the Twilight, shall rise in that fateful hour,
And decide the victor with my almighty hand."

~twilightinthedark~