This is Experiment 17 in the Sonic GeneX series. After years of effectively playing Frankenstein, Bucky finally actually created something from random parts. Bolt has a turtle shell, a bat head, and a chinchilla tail. He can't retract his head into his shell due to the bolts sticking out.

Bolt is shy and awkward, and if he thinks you're making fun of him, he tends to spark up with electricity in defense. Only the singing of Experiment 18, Sonata the Unicorn, can relax him when he gets whipped into a frenzy.