Sonic the Hedgehog in Castle Robotnik

It's the FrankenSonic monster! In this, the fourth book in the series, Doctor Robotnik plots to defeat that pesky hedgehog once and for all - by building a bolt-together version of Sonic. Wherewolves, vampires and mummies lie in wait for Sonic and his sidekick Tails as they venture into Robotnik's mountaintop castle for a cataclysmic confrontation.