The Mad Masker is a store located in Pelagius's Mind. It sells wacky and strange masks that can be displayed in the Hall of Oddities.
To get to Pelagius's Mind, you need to complete the quest 'The Mind of Madness' given to you by Dervenin in Solitude. The quest will require you to go to Pelagius' Wing in the Blue Palace. After quest completion, you will be able to return to Pelagius's Mind by equipping the Wabbajack and using Pelagius' Hip Bone when in the Blue Palace or Pelagius Wing. To get back to the door of the Blue Palace, use the bedroll inside Pelagius's Mind.
As Mad Masker was dropped with V5, this location is no longer available.
- Mario the Mara Love
a single master locked boss chest with some random loot. The chest can only be opened when returning after the completion of 'The Mind of Madness'. This is because all equipment will be removed from the player during the quest.