Monstrous scorpion

Monstrous scorpions or giant scorpions were a breed of arachnids known for their poisonous stingers. They were found in a variety of climates, but are most numerous in deserts.

Description
Giant scorpions are the size of horses. They were perfectly content with attacking whatever prey was smaller than themselves, including humans.

Combat
Scorpions were active hunters. They tracked their prey with their keen senses and then grasped it with their scissor-like pincers. Once in the scorpion's grasp, the prey was stung repeatedly until it stopped moving. It was then consumed by the arachnid, whether or not it was still living.

Lairs
Scorpions lived in underground burrows. As such, giant scorpions were often encountered in underground ruins or crypts.

Sourcebooks

 * Anauroch: The Empire of Shade
 * Lost Empires of Faerûn