Mask of Scents

The Mask of Scents is a pig face-shaped mask from.

Location
The Mask of Scents is given to Link by the Deku Butler, but only if he beats him in his race. After clearing the Woodfall Temple and bringing the Deku Princess back to Deku Palace, Link needs to talk to the Deku Butler. He's waiting to meet the young hero in the Deku Shrine outside of the palace. Once there, he will ask Link to race him, a race that is far easier to complete with the Bunny Hood equipped. If Link manages to keep up, he will say how it reminds him of racing with his son, and gives him the Mask of Scents in return.

Uses
It imbues the wearer with the ability to sniff for the scent of and find Magic Mushrooms, two of which are given to Kotake to create Blue Potions. Because Blue Potions can be bought elsewhere (although for more Rupees), and given the obscurity of the mushroom's location, the use of the mask is relatively rare; however, Link can still receive a free Blue Potion in exchange for the Mushroom.

Link's voice changes when the mask is donned, and he snorts and grunts like a pig when he rolls or swings his sword. Mushrooms will appear as a cloud of purple mist and can be scooped into a bottle. The mask is owned by the Deku Butler, but was originally owned by his son.

Trivia

 * On the third row of the Mask Subscreen, the Keaton Mask (Fox), the Bremen Mask (Falco), the Bunny Hood (Peppy), Don Gero's Mask (Slippy), and the Mask of Scents (Pigma) are said to represent Starfox characters, implying that Nintendo created the appearance of these masks (save for the Keaton Mask and Bunny Hood, both of which appeared in Ocarina of Time) with the sole purpose of hiding an easter egg in the game itself.
 * If Link puts on the Mask of Scents while in the Stock Pot Inn, a purple fume cloud can be seen in the performers' room protruding from the pair of boxers on a bed, and another fume cloud can be seen coming from the toilet down stairs. In these places, mushrooms can be obtained with the Bottle.