The official GemStone IV encyclopedia.
A barely visible spirit, the phantasma floats silently across the room. Its bald head, thick neck, muscular forearms and fixed sneer reflect its former positions of jailer and torturer. Rotting leather armor drapes the phantasma, providing it with its only solid link to the living past.
Phantasmas can cause a severe amount of damage with its Disintegrate (705) spell. Be sure to spell up appropriately with TD boosting spells, such as Spirit Warding.
Phantasmas are immune to some "unbalance" damage crits, such as those caused by Unbalance (110).
Phantasmas can emit a "hollow moan" that dispels sanctuaries.
Like most non-corporeal undead, phantasmas will decay on their next acting tick if they are not immediately looted upon death.
They have an attack that can knock you down in offensive, stunned, and drain spirit:
A phantasma's eyes flash a bright, ghostly blue as it stares deeply into your eyes!
An explosion of intense pain fills your mind, and you reel, captured by the phantasma's dreadful stare! You futilely try to scream as a tortuous wave ripples through your body, leaving you writhing as you collapse!
You feel drained!