A bubble-producing device includes a container for receiving a quantity of a bubble-forming liquid to a desired liquid level in the container; a bubble-forming loop moveable within the container to a lower position below the desired liquid level so as to be submerged in the liquid when received within the container, or to an upper position emerged from the liquid; and a controlled gas supply system for controlling the introduction of a gas (e.g. air) into the container effective: (a) first to move the bubble-forming loop from its lower position submerged in the bubble-forming liquid, to its upper position emerged from the bubble-forming liquid; and then (b) to discharge gas through the bubble-forming loop and thereby to produce a bubble therein. Embodiments are described wherein the bubbles are produced at a distance to serve as targets for a water gun, and wherein bubbles of different colors are produced.