just shoot me DON'T PANIC! What the Hitchhiker's Guide to the Galaxy has to say about Sparky:

Squirrel Monkeys are native to the planet Koochi-Coo, the primary source of all cutesy little critters throughout the entire universe. The original Squirrel Monkey was genetically engineered by former evil Nazi scientists who kept their brains alive in jars which were subsequently hired by a top secret para-military organization of animal rights activists called the "12 Monkeys." The ultimate goal of this group was to create the pen-ultimate "13th Monkey" which could perpetuate its own kind despite repeated attempts by all civilized space-faring races to eradicate unbearably cutesy lifeforms from the face of the multi-verse. The Squirrel Monkey was the most successfull genetic hybrid the 12 Monkeys ever produced, a cutesy little critter which could adapt to an extremely wide variety of atmosphereic conditions and was able to ward off predators by emmiting a nasty jolt of electricity. It is rumored that Squirrel Monkeys are asexual (no one has ever been brave enough to actually check up on this) and that it only takes one Squirrel Monkey to populate and entire planet. These insidious beasties have spread to almost every corner of the galaxy simply by being cutesy and relying on unwary passers-by to mistake them for stray pets. Mostly harmless, but will eventually eat you out of house and home, so if you ever see one, run in the opposite direction as fast as you can lest you succumb to its cutesy charms.