Bob is a momma's boy who is the brawn to Toshiaki's brains. He is agreeable and never mean-spirited, but on the flip side he's easily led and gullible. Bob follows Toshiaki everywhere, but is the first one to run to Victor for help when he gets in over his head.

Edgar "E" Gore is a needy misfit who doesn't have friends but is desperate to be Victor's partner for the science fair. In his attempt to be accepted, "E" tends to mess things up and often fails to think before he speaks. Even though "E" promises not to tell Victor's secret, he accidentally spills the beans.

Sparky is a devoted and playful bull terrier whose sense of curiosity is matched only by his beloved owner, Victor. Sparky enjoys chasing after balls and being the star of Victor's homemade movies. He exudes tons of energy and enthusiasm.

Toshiaki is over-achieving and mega-competitive. He delights in beating Victor at his own game and like a power-hungry, mad scientist, Toshiaki will stop at nothing to win the top prize in the school's science fair-even if it means stealing Victor's ideas to do it.

Victor Frankenstein is a clever and industrious 10-year-old boy who is inspired by science. He lives with his parents and dog, Sparky, in the town of New Holland. Victor immerses himself in making films and inventing in his attic workshop. When he loses Sparky, Victor use scientific ingenuity to bring him back to life.