A weapon accessory integrates multiple illumination sources and a mechanism for dispensing a chemical irritant within a single housing for attachment as a fore grip to a firearm. The weapon accessory has selectable microprocessor-controlled multi-modes of operation for providing illumination, sighting or target debilitation. Switches on the outside of the housing enable user setting and control of the multiple modes of operation, which include one or a combination of (i) activating high intensity light emitting diodes (LEDs) to illuminate an object or human subject with either visible or infrared light, (ii) activating a visible or infrared laser for sighting a target, (iii) activating a frequency modulation mode that alternates pulsing white and blue LEDs at three superimposed frequencies to temporarily disable, distract and degrade the vision of a human subject, and (iv) activating the chemical irritant dispenser.