Zora Mask

The Zora Mask is a mask that appears in The Legend of Zelda: Ocarina of Time and The Legend of Zelda: Majora's Mask. As its name implies, it is in the shape of the face of a Zora.

The Legend of Zelda: Ocarina of Time
The Zora Mask in The Legend of Zelda: Ocarina of Time is one of four special masks rewarded to Link for completing the Happy Mask side quest. It has no special features and is mostly used for comedic purposes such as getting odd reactions from other people.

If Link shows the Zora Mask to King Zora XVI he will think he is being mocked. While the other Zoras (except for Princess Ruto) basically say Link looks nothing like one of their race, Princess Ruto's dialogue seems to indicate that she believes Link to be a Zora and asks if he's ready to marry her, although she could simply be playing along.

The Legend of Zelda: Majora's Mask
The Zora Mask is the third of four transformation masks Link must obtain during his travels in Termina. The mask allows him to transform into the Zora guitarist, Mikau of the Indigo-Gos, and use his special abilities. The Zora Mask is needed to navigate the currents of Great Bay Temple, as well as to infiltrate the Pirates' Fortress and to explore Pinnacle Rock.

Obtaining
When Link first enters Great Bay, he finds a dying Zora named Mikau floating near the shore. Gerudo Pirates fatally wounded him when he attempted to rescue the eggs of a fellow band member named Lulu. Link pushes him towards the shore, but his wounds are too great. Link plays the "Song of Healing" to heal his soul, and Mikau plays one last song explaining his dilemma, then his body disappears in a flash of light, leaving the Zora Mask imbued with his spirit. Link takes the mask with him, and whenever he puts it on, he transforms into Zora Link, which appears to be a combination of Mikau's body and his own. Link is able to impersonate Mikau while in his Zora form, which allows him to help The Indigo-Gos and their singer, Lulu. When Link tries to play his Ocarina of Time while wearing the Zora Mask, he discovers he had gained the ability to play Mikau's Guitar of Waves.

Powers
Zora Link can breath underwater, sink to the bottom of a body of water to perform terrestrial actions such as walking, and becomes a quick and agile swimmer. Zora Link's offensive capabilities includes using a pair of fins on his forearms as short and long-range weapons (similar to the sword and the boomerang, respectively). On land, Zora Link is able to use an advancing back flip attack, that performs a similar, albeit slower, function to Link's jumping slash. Pressing R while on land causes Zora Link to use a large fin as a shield. He can also create a more effective electrical shield around himself underwater by pressing the R button and on land by pressing the R and B buttons simultaneously, though this drains his Magic Meter. Link is very vulnerable to fire and ice attacks in this form and will take additional damage he would not normally incur.

Link can also use this mask to trick the other members of the Zora band, The Indigo-Gos, into believing he is Mikau and give him information regarding the band's troubles, allowing Link to help them.