The Spectral Elixir is a unique Potion that is received when the Black Mushroom quest is completed in the original Diablo.
In game
The Spectral Elixir is created by Pepin when the player brings him a Demon's brain. The player is asked to bring the Spectral Elixir to Adria but as she no longer needs it upon the quest completion, the player is allowed to keep it.
When the player consumes the Spectral Elixir, all stats are increased by 3.
Diablo I
Recovery — Healing Potions • Mana Potions
Elixirs — Elixir of Strength • Elixir of Vitality • Elixir of Magic • Elixir of Dexterity
Quest Potions — Golden Elixir • Spectral Elixir
Demo only elixirs — Elixir of Clumsiness • Elixir of Disillusion • Elixir of Weakness
Diablo II
Recovery — Healing Potions • Mana Potions • Rejuvenation Potions • Antidote Potion • Thawing Potion • Stamina Potion
Throwing — Poison Potions • Fire Potions
Quest Potions — Potion of Life • Malah's Potion
Diablo III
Recovery — Health Potions