Aquabot is a replacement cap for your water bottle that is equipped with a pump-action pressurizer, allowing you to turn otherwise harmless-looking water bottles into highly lethal super soaking cannons.
As with any regular bottle of household cleaning solution, the Aquabot's twistable nozzle allows you to choose between a harmless mist and a 25-foot stream. You can even completely remove the nozzle for a hardcore firehose-like effect that is sure to piss off your unsuspecting victim. It could also be used for less debaucherous activities such as getting dirt off dishes while camping or putting out a campfire.
The developers of Aquabot successfully ran a Kickstarter campaign to raise funds for production of their game-changing invention. A pledge of $18 will get you one of these if and when they're ready to ship.