NPCs composing that spawngroup :

an_army_behemoth (10%)

a_fog_golem (50%)

a_mist_golem (40%)

NPCs spawning around that spawngroup :
(Max range : 100)

citymist_127, range=70 (-171,-8,296)

a_mist_golem (50%)
greater_war_boned_skeleton (50%)

citymist_50076151, range=48 (-194,-28,295)

citymist_50076157, range=96 (-259,-8,77)

citymist_50076169, range=72 (-174,-5,-13)

citymist_50076170, range=17 (-188,-59,291)

gyrating_goo (100%)