NPCs composing that spawngroup :

an_obsidian_lava_spider (100%)

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

pofire2170447, range=81 (-250,1294,-163)

a_greater_magma_rocklord (99%)
Magma_Overlord (1%)

pofire2170499, range=74 (-204,1269,-177)

a_great_flame_lord (100%)

pofire2170575, range=74 (-160,1411,-194)

a_fiery_spirit_equine (50%)

pofire2170603, range=79 (-105,1337,-194)

a_giant_obsidian_lava_spider (99%)
Dark_Obsidian_Lava_Spider (1%)

pofire2170608, range=75 (-237,1286,-175)

a_fiery_spirit_equine (100%)

pofire_288803, range=81 (-250,1294,-163)

A_Chaos_Magma_Rocklord_# (100%)

pofire_288917, range=74 (-160,1411,-194)

pofire_288918, range=0 (-184,1341,-186)

An_Obsidian_Magma_Spidering_# (20%)
An_Obsidian_Magma_Spider_# (80%)

pofire_288922, range=74 (-204,1269,-177)

A_Greater_Magma_Lord_# (50%)
A_Magma_Elemental_# (50%)

pofire_288925, range=79 (-105,1337,-194)

#The_Fabled_Dark_Obsidian_Lava_Spider_# (6%)
An_Obsidian_Magma_Spider_# (94%)