NPCs composing that spawngroup :

an_explosion (12%)

an_immobilizer (8%)

an_inactive_trap (8%)

a_dark_entity (8%)

a_formless_terror (8%)

a_magi_construct (8%)

a_null_field (8%)

a_spike_trap (8%)

a_tanglefoot_trap (8%)

a_wardstone (8%)

a_wave_of_cold (8%)

a_wizard_construct (8%)

NPCs spawning around that spawngroup :
(Max range : 200)

necropolis_14, range=35 (-201,-1015,-255)

necropolis_19, range=182 (-225,-1181,-311)

an_entropy_serpent (50%)
an_entropy_serpent (50%)

necropolis_39, range=154 (-237,-845,-256)

a_Chetari_Deathbinder (50%)
a_Chetari_worker (50%)

necropolis_54, range=101 (-180,-912,-256)

a_Chetari_Dominator (50%)
a_Chetari_worker (50%)

necropolis_61, range=93 (-262,-1088,-288)

an_entropy_serpent (50%)
an_entropy_serpent (50%)

necropolis_72, range=190 (-137,-1164,-281)

an_entropy_serpent (50%)
an_entropy_serpent (50%)

necropolis_162, range=96 (-274,-911,-255)

a_Chetari_Deathshaper (100%)

an_inactive_trap_190081, range=140 (-292,-871,-248)

an_inactive_trap_190085, range=57 (-176,-1000,-248)