Alter Aeon Online Help

Keywords are:  'necromancer spell coffin'

Spell: coffin                   Mana:  51  Int: 35  Wis: 33  Lvl 38 Necr  (28%)
                                (helpful)   Requires: bone prison
                                Group: Necromancer Dragontooth Skills
                                Damage Type: crush
                                Damage: massive (special, see text)  

Usage:
cast coffin <target>

The 'coffin' collapses any magic prison, crushing whomever is
trapped inside.  Though first developed to be used on bone prisons,
it also can be used effectively with ice or crystal prisons.  The
attack is especially devastating, as the victim has no means of
escaping it.

Alternatively, the spell can be used to liberate an ally from a
bone prison, as it is the only spell that can destroy a bone prison
safely.