Spell Allergy (3.5e Trait)
From D&D Wiki
You sneeze every time you are in close proximity to magic.
Benefit: Due to your sensitivity to magic, you can automatically detect and locate magical items within 30' (otherwise as the Detect Magic spell).
Drawback: Every time you are within 20' of a magical item, you must make a fortitude save to resist sneezing. The more powerful the item, the louder the sneeze. The sneeze gives any being in the vicinity a +1 to listen checks.
You also sneeze when you are within 20' of a caster (automatic; no save allowed).
If you are within 10' of a magical artifact or divine creature, you automatically breaks out in hives, which give you a -2 on all d20 rolls unless you make a Fortitude Save (DC 16).
If you are a caster you become alergic to yourself (except when you are in an antimagic feild) you sneeze every 1d4 min.
Roleplaying Ideas: Your party memebers may use this to gauge enemy threat level or to find the best magical goodies..... dont put them on. "Looks like a caster, how dangerous is he Richard?" "ACHOOOOOOO!" "Very dangerous, thank you."