Scorpion tail

The severed tail of a radscorpion. It appears in Fallout, Fallout 2 and Fallout: Brotherhood of Steel.

Usually obtained from recently-deceased radscorpions, though a few can be found elsewhere. Myron uses them to make the antidote, as does Razlo in Shady Sands.

One can be used to poison the Wright's still. Over time, the citizens of New Reno will start dying. This doesn't effect any family members, but it will kill Father Tully. The intelligent radscorpion's tail can be removed while still alive without consequence as long as the player isn't caught.

In Fallout: Brotherhood of Steel, it used for the quest Collect Radscorpion Tails

Fallout

 * Scorpion tails will be in the inventory of all radscorpions on death.
 * If the player speaks to Aradesh and agrees to help his people by destroying the radscorpions, they will begin the quest Stop the Radscorpions. Part of the quest involves eliminating radscorpions inside their caves. There are a total of nine radscorpions inside the caves.
 * Radscorpions will spawn around the entrance to Vault 15 the first time the player visits.
 * You can randomly encounter radscorpions anywhere on the world map.

Fallout: Brotherhood of Steel

 * Armpit needs radscorpion tails for his liquor recipe.