From The Improbable Island Contestant's Survival Guide, Season 2 Edition.
This is a particularly fancy-schmancy prototype weapon of mass destruction, created by the scientists in Improbable Central, stolen by Kassil, and rumored to be hidden somewhere on the Island. A smaller, single-attack version of this weapon is available wherever fine armaments are sold, but that version does not have the special multi-attack overkill settings that make this prototype so devastating.
If you encounter Foilwench in the jungle, please check for dangerous time-distortions. Foilwench never ventures outside the Common Ground these days.