Publication:Dread Codex/New Spells/Flame Symbol

Undead creatures animated by you are imbued with a burning sigil that floats just above their heads. The body of the creature radiates heat, and its eye sockets smoke and burn with orange flame. The spell affects a number of hit dice of animated undead equal to your level.

Undead with the flame symbol gain the fire subtype as an extraordinary ability, granting them fire immunity and exposing them to double damage from cold except on a successful save. Additionally, undead affected by the flame symbol inflict an extra 1d6 points of fire damage when they strike with a natural weapon. Creatures touching or striking the symbol-bearing undead with a natural weapon also suffer this damage. This spell does not stack with other symbol spells.