Piece of Power
Piece of Power is an item from Link's Awakening.
Pieces of Power are small flashing triangles that sometimes materialize after Link defeats an enemy on Koholint Island. Their only function is to temporarily increase Link's sword-based attacks. While the Piece of Power is in effect, special music plays and Link's sword icon flashes. This power-up either expires after a short time moving around or terminates upon entering or exiting a cave or building.