Sparky resembles a yellow chinese dragon/monkey/lightning bolt shaped creature with a small body, large oval-shaped head, a pair of long protruding antennas, two blue eyes, a wide mouth, a wiry tail, a pair of triangular ears, two short arms, and two stubby legs. His body can also transform into a streak of electricity, allowing 221 to travel through electrical-powered machines and short circuit them.
Sparky's main function is electrokinesis. He can create massive crippling power surges, shoot lightning blasts from his antennas, and release a massive discharge of electrical energy. Sparky can also travel through electric-powered appliances and machines, short-circuiting them in the process.
Sparky first appeared in Stitch! The Movie. He was first activated by both Lilo and Stitch when they needed an experiment to recharge Jumba's ship in order to rescue Jumba from Dr. Hämsterviel. However, Sparky escaped Lilo's house, rampaged throughout Kauai, and short-circuited some portions of the entire Hawaiian town. Eventually, Lilo and Stitch successfully captured Sparky at the local hotel. Sparky later stowed away on Gantu's ship, rescuing Stitch and Lilo after creating a power surge on Gantu's ship, then making an escape in Dr. Hämsterviel's ship. Finally, at the near end of the movie, Lilo decided that the abandoned lighthouse, which had previously been too expensive to light, would make a great home for Sparky.
Sparky also appeared in several episodes of Lilo & Stitch: The Series, as well in Kingdom Hearts: Birth by Sleep as a boss character for Terra's story mode.