See also: Spell Combinations: Shattering

Codex text

A creature frozen or petrified by magic, as from the spells Petrify or Cone of Cold, is in a vulnerable state, subject to shattering if excessive force is applied to just the right spot. A critical hit from any weapon may suffice, and the spells Stone Fist and Crushing Prison have been known to achieve the effect as well.

Further information

Instant kill (higher levels can resist). Critical hits can be from Slam, Shred, Overpower, Riposte, Cripple, Punisher and Critical Strike. Note that critical hits from Pinpoint Strike do not shatter opponents.