NPCs composing that spawngroup :

an_apparition (25%)

an_apparition (25%)

a_vapor_golem (50%)

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

citymist_44, range=42 (256,34,4)

citymist_51, range=1 (250,-9,4)

plaguebone_skeleton (100%)

citymist_52, range=56 (194,-14,-9)

citymist_57, range=85 (219,-88,1)

citymist_91, range=69 (280,-71,75)

citymist_223158_takp_import_v0, range=39 (278,20,75)

gyrating_goo (50%)
gyrating_goo (50%)

citymist_222975_takp_import_v0, range=25 (230,8,5)