NPCs composing that spawngroup :

#The_Fabled_Fellspine (15%)

a_coldspine_seahorse (30%)

Fellspine (55%)

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

sirens_16, range=63 (-555,202,-154)

sirens_40, range=48 (-513,150,-151)

sirens_41, range=65 (-544,155,-152)

sirens_288190, range=63 (-555,202,-154)

##_a_coldspine_seahorse (100%)

sirens_288191, range=0 (-492,194,-155)

##_a_coldspine_seahorse (50%)
##_Fellspine (50%)

sirens_288193, range=48 (-513,150,-151)

##_a_coldspine_seahorse (100%)
##_a_coldspine_seahorse (100%)