The Witchdoctor mask is an item obtained from Herblore Habitat. Players receive this item as a reward from Papa Mambo when you've managed to catch all three of the God Jadinkos at least once in the same week that you caught all ten of the normal Jadinkos.
In order to attain this item, you must have 81 Hunter, 77 Farming, 54 Herblore, and 55 Agility. Boosts can be used to meet all of these level requirements.
The mask's primary function is its right click teleport that allows a player to teleport directly to Herblore Habitat any number of times. In addition, the mask gives a 2% experience boost when training farming, hunter, or herblore within the Herblore Habitat.