Mute Screaming Maw is very rare, with only three samples in the whole of the Shivering Isles. One each can be found in Corpserot Prison, Dunroot Burrow, or Cann. Should you be willing to use one of these rare samples, it shares all the same effects as their common counterpart, Screaming Maw, allowing you to make potent multiple effect potions. The ingredient's normal FormID is 00081E9A, while the other variant, 00081EA5, only occurs when that object is handed over as part of the Museum of Oddities questline, making that variant only accessible by console commands.