Glowing Scorpid Blood

Source
This item can be looted from most scorpids in Azeroth of level 50 and higher. You can find them in Silithus, the Blasted Lands or the Burning Steppes, a few scorpids can also be found in Blackrock Spire and Blackrock Depths.

As a quest objective

 * Glowing Scorpid Blood (quest)
 * More Glowing Scorpid Blood