NPCs composing that spawngroup :

an_alarm (12%)

an_inactive_trap (12%)

a_dark_entity (12%)

a_low_hum (12%)

a_null_field (12%)

a_spike_trap (16%)

a_wave_of_cold (12%)

a_wizard_construct (12%)

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

necropolis_44, range=114 (1465,664,-155)

an_amorphous_mass (50%)
an_amorphous_mass (50%)

necropolis_45, range=125 (1457,656,-155)

an_amorphous_mass (50%)
an_amorphous_mass (50%)

necropolis_46, range=151 (1556,914,-150)

an_amorphous_mass (50%)
an_amorphous_mass (50%)

necropolis_47, range=141 (1548,906,-151)

an_amorphous_mass (50%)
an_amorphous_mass (50%)

necropolis_48, range=164 (1502,935,-146)

an_amorphous_mass (50%)
an_amorphous_mass (50%)

necropolis_49, range=156 (1494,927,-148)

an_amorphous_mass (50%)
an_amorphous_mass (50%)

necropolis_50, range=142 (1384,844,-90)

an_amorphous_mass (50%)
an_amorphous_mass (50%)

an_inactive_trap_190119, range=140 (1366,769,-82)

an_inactive_trap_190124, range=115 (1471,661,-153)