The Mad Scrub is an enemy that appears in Ocarina of Time and Majora's Mask. It is a relative of the Deku Scrub and seems to be a frenzied version of the regular business happy Deku Scrub. It is an almost exact look-alike from the regular Deku Scrub. The only difference is its autumn leaf. Its skin is also slightly greener; both of these differences signify its madness. These ferocious Deku Scrubs generally live in swamps and forests as the Mad Scrubs are only found in those environments.
The behavior of the Mad Scrub is well known for the fact that it won't back down to sell Link items or tell him hints, but instead runs away from Link until it gets back to its plant. It also shoots three Deku Nuts instead of one. Like its relatives, it hides from Link if he gets too close.
Ocarina of Time
The Mad Scrubs in Ocarina of Time are first found in the Sacred Forest Meadow as a child while searching for Saria in the Lost Woods. As an adult, they are found in the Kokiri Forest, being controlled by malevolent enemies under the actions ensued by Ganondorf. After Link completes the Forest Temple, the enemies are no longer found in the Kokiri Forest, and the Kokiri children have come out of their houses safely.
That's one Mad Scrub!
The Mad Scrubs in Majora's Mask are found within Woodfall. They appear on the wooden tree stumps and spit rocks at Link whenever he is adjacent. After they are defeated, their flower turns into a Deku Flower.