"Hey, wait a minute! ... Please don't tell me you're seriously considering drinking that Mystery Milk?! Don't be hasty! Remember, we have no idea what's really in that stuff. So don't do it! Got it? If you drink that milk, I'm ending our friendship!"

Mystery Milk is an item from The Legend of Zelda: Majora's Mask, exclusive to the Nintendo 3DS remake of the game. It is a special type of milk concocted by the Gorman Brothers that posssesses the ability to cure stomach aches. The milk can only retain its freshness for two minutes before becoming spoiled, at which point it transforms into useless Moldy Milk.

If Link approaches Gorman at the Stock Pot Inn during the first half of the Second Day with the Circus Leader's Mask on, Gorman will explain that he has contracted a stomach ache from overindulging on milk the night before. This has, in turn, discouraged him even further from informing his troupe members that their scheduled Carnival of Time performance has been cancelled. He asks of Link to go to his brothers and receive Mystery Milk so as to aid his recovery.

Upon Link's arrival at the Gorman Track, Gorman's brothers immediately understand the circumstances and promptly provide Link with a bottle of Mystery Milk, apparently made, at least in part, from natural ingredients found on the ground. The delivery cannot be made until the afternoon of the same day, and the Mystery Milk must also be delivered before the passing of two minutes upon receiving it. Gorman revives instantly upon receiving the milk, and eventually tells his troupe of their situation after an unseen meeting occurs. As a reward, Link receives the discarded bottle from Gorman.

Link cannot use the "Song of Soaring" or the Goron Mask to travel to Clock Town to make his delivery, as Tatl claims the contents are likely to spill should he use this method of transportation. Should Link fail to make the delivery on time, the resulting Moldy Milk will occupy Link's bottle, rendering it unusable, until time is reset. If given the Moldy Milk, Gorman will react with extreme discomfort at its smell, humorously described by the game as smelling "worse than a Goron's armpit." Tatl will also dissuade Link from drinking the milk, regardless of its current condition. Moldy Milk is also one of the few bottled items that the Man from the Curiosity Shop will refuse to buy.