Pedipalp

A pedipalp, also known as a whip scorpion, was a type of arachnid found across Toril, especially in the Underdark.

Description
Pedipalpi were essentially a cross between the two common arachnids: spiders and scorpions. These creatures came in many colors, mainly shades from green to red. All had a poison-sack that was the size of a fist and resembled a walnut.

There were three types of pedipalpi:
 * Schizomids: small pedipalpi without whip-like feelers and stingers.
 * Amblypygi: medium-sized pedipalpi without stingers.
 * Uropygi: the largest of pedipalpi, powerful and very rare.

Behavior
Pedipalpi were wanderers, as well as aggressive hunters. They roamed without fear in search of food and established no permanent territory. They almost always hunted smaller prey alone or in pairs, but often teamed up in small groups to take down larger opponents. These arachnids didn't harm others of their kind.

Whip scorpions mated every 8 months, where the female produced 2–40 eggs. Instead of protecting these eggs, both members of the couple incapacitated another creature and laid their eggs inside. The young would spawn and act as a parasite, eating their way out of the host.

Combat
Each type of pedipalp was immune to all toxins and poisons, even acids and noxious vapors. They were often solitary combatants, and never hunted in large packs. They would attack with whatever natural defenses they had available, from their pincers to deadly poison.

Ecology
Pedipalpi were used by the drow as familiars, pets, household guardians, and hunters. Their fist-sized poison sacks were sought among thieves and merchants. The powerful poison could disable many a foe. Their foreleg pincers could be torn off and used as maces, which were somewhat popular among goblinkin. The feelers of the pedipalpi could be used as whips, but would not be effective after about a week.

Appearances

 * Video games
 * Menzoberranzan