- "Daily trying to get to the bottom of the mysteries of Lake Hylia!"
- — Sign
The Lake Scientist is a character from The Legend of Zelda: Ocarina of Time. Known only by his occupation, he is an eccentric old man who spends his time researching bodies of water and their many mysteries. The Lake Scientist mentions, at one point, that Granny was once a student of his.
The Lake Scientist performs his research in the Lakeside Laboratory, where he researches the many mysteries of Lake Hylia and the sea. He plays a role in the trading quest for Biggoron's Sword, where Link must deliver the Eyeball Frog to him before it is spoiled. The old man initially assumes the frog is a present for him from King Zora XVI, as the eyes of Eyeball Frogs are known delicacies. He is disappointed to hear that it is needed to create the World's Finest Eye Drops for Biggoron. Despite this, he extracts the proper ingredients from the frog and fills a vial with the efficacious eye drops. Link must deliver this to Biggoron before it spoils in four minutes.
Also, in the Lakeside Laboratory, there is a deep aquarium. Link can dive into the water in this aquarium and after he resurfaces, the Lake Scientist, having watched him dive in secret, will judge his dive. Once Link retrieves the Golden Scale, he can dive to the very bottom of the pool. The Lake Scientist is so impressed that he gives him a Piece of Heart.
The Lake Scientist appears in the manga adaptation of Ocarina of Time, in which he is given the name Dr. Mizumi. After Link discovers an injured Prince Rouru, he rushes him to the Lake Scientist's lab, where he later discovers that Prince Rouru is a Watarara.