Abstract: Toys and toy operating systems for use therein. A toy operating system may include an input system responsive to a predetermined quantitative characteristic of a liquid body, such as electrical conductivity, and a response system coupled to the input system and configured to generate one or more toy output patterns based at least in part on the given characteristic. A toy vehicle for use with such an operating system may include a chassis, a chamber adapted to contain a liquid body, and at least one toy component operable to display an output according to a generated output pattern. Exemplary toy components include an audiovisual assembly to produce an audiovisual display and a drive assembly to move the toy vehicle across a ground surface.