†These items are considered poisons, not alchemy ingredients.
Magebane is a substance that has the poisonous properties of greatly decreasing magicka while also draining willpower.[1] It can be created by combining ghostessence, Werewolf's blood, and rubies together.[2]:177
†Malachite in Skyrim is not used in alchemy, but can be used to craft glass armor and weapons. ‡This is used for crafting, but is not an alchemy ingredient.
Mort Flesh refers to the myriad of different appendages that have been harvested from the reanimated dead—Mort fingers, mort tongues, and mort hearts. Careful handling is important, as mort flesh carries several potentially fatal diseases such as Ataxia, Helljoint, and Witbane.[3] It has several uses in both alchemy and enchanting. It has a sweet sickly odor.[3]
Muck is the damp, fibrous slime from crushed muckspunge plants that grow in the West Gash, and Azura's Coast regions of Vvardenfell. Unless properly prepared, it is mildly toxic.
Mummy wrappings are the cloth wrappings which were used in the preservation of a mummified corpse. Some alchemy recipes call for freshly harvested wrappings from a specific mummy.[4]