Dark Link

Dark Link is a mini boss in Ocarina of Time. He can be found in The Water Temple in a seemingly endless room. He mirrors every one of Link's attacks and even copies Link's movements, even the one of him yawning and scratching his leg. To be defeated, a hammer maybe useful, or you could L/Z target him and do a horizontal slash on the opposite side of his shield for an instant hit. When defeated the prize is a Longshot, the extended version of a Hookshot.