A fleshrot

Fleshrot zombies appear as part of the Zarvonn's Valley: Eternal Gorge Ring Event. They are the third wave of non-named undead to spawn in that sequence. They are popped in a bunch in the doorway of each of the buildings in the zone, and after several seconds they wander out and about in the area surrounding their building.

They will appear in two or more waves, with around a five minute timer between death of one wave and the start of the next.

They drop nothing other than what's on the standard loot table: occasional coin, a status relic, or an occasional curiosity treasure.