Ghostly Fireball
Version 0.13: This article may not be up to date for the latest stable release of Crawl.
Ghostly Fireball is a monster-only spell which behaves much like the Fireball spell, dealing heavy, unavoidable damage to everything caught in its 3×3 blast radius. Unlike Fireball, however, it deals partially-irresistible negative energy damage, ignores half of its victim's AC, and heals any undead affected by it.
The following enemy casts Ghostly Fireball:
History
Ghostly Fireball will be added in 0.13.