The Insufferable Miscreant
The Insufferable Miscreant, Hindering Obstructionist is a type of Treasure Goblin, added in patch 2.2.0 of Diablo III.
It is always accompanied by Vault Peons that run a distraction for it, and can summon more at will. To be easily recognized, Insufferable Miscreants have an armored grey appearance. They drop more weapons and armor than normal Goblins.
Goblins
Treasure Goblins: Blood Thief • Gelatinous Sire • Gem Hoarder • Gilded Baron • Insufferable Miscreant • Malevolent Tormentor • Menagerist • Odious Collector • Rainbow Goblin
Treasure Realm: Vault Peon • Vault Sentry • Baroness Greed
Other: Snitchley • Herald to the Queen