Symbol of Insanity(Player's Handbook v.3.5, p. 290)
Enchantment (Compulsion) [Mind-Affecting]
Level: Cleric 8, Sorcerer 8, Wizard 8, Wu Jen 8, Sha'ir 8, Death Master 8,
Components: V, S, M,
Casting Time: 10 minutes
Range: 0 ft.; see text
Effect: One symbol
Duration: See text
Saving Throw: Will negates
Spell Resistance: Yes
Unlike symbol of death, symbol of insanity has no hit point limit; once triggered, a symbol of insanity simply remains active for 10 minutes per caster level.
Note: Magic traps such as symbol of insanity are hard to detect and disable. A rogue (only) can use the Search skill to find a symbol of insanity and Disable Device to thwart it. The DC in each case is 25 + spell level, or 33 for symbol of insanity.
Material Component: Mercury and phosphorus, plus powdered diamond and opal with a total value of at least 5,000 gp.