Odious Collector

The Odious Collector, Purloiner of Fine Things is a variant of the Treasure Goblin in Diablo III, introduced patch 2.1.2. They always drop piles of Crafting Materials instead of normal loot when killed (including Death's Breaths and Forgotten Souls) with a high chance of dropping crafting recipes that are still missing in your collection. While running, they also leave a trail of Reusable Parts, Arcane Dust and Veiled Crystals.

Visually, they glow green to distinguish them easily.