Instead of an ear-piercing wail, the device unleashes the chemical compound allyl isothiocyanate, which gives horseradish, mustard, and wasabi their bite. A red LED on the alarm also starts flashing when smoke is detected.
In tests on sleeping people with normal or no hearing, the device woke nearly all subjects up within two and a half minutes after the stench hit their nostrils. Further tests determined the ideal intensity of airborne wasabi to wake people up but not hurt their eyes in the process.
From CNet News, I knew there was a use for this stuff.