NPCs composing that spawngroup :

a_thought_leech (50%)

a_thought_leech_spiriter (50%)

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

thedeep_a_shrieker34, range=71 (242,162,-59)

thedeep_224969, range=97 (131,272,-58)

an_enthralled_outcast (50%)
An_Enthralled_Underbulk (50%)

thedeep_224985, range=28 (191,227,-59)

a_thought_leech_evoker (50%)
a_young_thought_leech (50%)