So the last achievement my group needs is "I Made a Food!" from Festerface in Violet Hold Mythic. Well, as you all know, Festerface is one of many bosses in there and it's completely random which one spawns. It also seems like the bosses don't change every week on Mythic, either that or my group had the same boss combo three times in a row when we tried to farm it.
Is this achievement literally unobtainable without waiting however many weeks to get Festerface to spawn? Are Blizzard really that stupid?