Sparky is a laboratory rat who befriends Gadget. He is a lab animal of Norton Nimnul, whom he admires and believes to be a genius. After leaving Nimnul's charge, he leaves for MIT with his cohort Buzz.
Sparky is a tall rat in a labcoat, thin except in the haunches and almost gangly. His light, short hair is tousled and spiked in all directions due to an excess electrostatic charge he always carries. His light-colored eyes and constricted pupils give him a look of intelligent mania.
Sparky is scatterbrained and easily distracted, even moreso than Gadget, and suffers occasional memory lapses that cause him to essentially repeat himself. His exposure to electroshock may aggravate his problems. Like Gadget, he does not perceive social nuances very well and is unaware of the destructive tendencies of Gadget's inventions, seeing them as experiements to be played with and tweaked.
Despite his shortsightedness, Sparky has a strong ethical code and believes firmly that science is to be put to good use. He is enraged when he learns that Nimnul is abusing it and instantly turns against Nimnul.
Sparky has been conditioned by Nimnul to operate as an automaton when he hears the sound of a whistle. His standard action in this condition is to find and hotwire an alarm bell to activate Buzz.
Sparky appears only in Does Pavlov Ring a Bell? He is inside a pile of junked electronics when Gadget, looking for parts, mistakenly pulls his tail.