- Were you looking for the World of Warcraft items
[Invisibility Potion] or 
[Lesser Invisibility Potion]?
This article contains lore taken from Warcraft III: Reign of Chaos, Warcraft III: The Frozen Throne, the manuals, and/or official bonus maps.
- Potion of Invisibility
50- Non-Combat Consumable
Renders the Hero invisible for 120 seconds when used. An invisible Hero is untargetable by the enemy unless detected. If the Hero attacks, uses an ability, or casts a spell the invisibility effect is lost. - 1 Charges
Renders the Hero invisible for 120 seconds when used. An invisible Hero is untargetable by the enemy unless detected. If the Hero attacks, uses an ability, or casts a spell the invisibility effect is lost.
Source[]
These can be bought from Goblin Merchants.