The Dragula was a drag racing car shaped like a coffin that Grandpa built in the 60's TV show The Munsters. Not sure if that's what the song is referring to, but given how much Rob Zombie likes old horror tv and movies and stuff, my guess is that's the most likely reference.
Maybe you just don't have the correct headspace and timing to understand. Are you a Poet Laureate? Are you an editor? What qualifications do you have to be the judge? Just cuz the lyrics are out of your reach doesn't mean they're out of the reach of others.