"Oh, Cedric, I can't believe you are dead/ Oh, Cedric, now you're in 'Twilight' instead/ Oh, Cedric, vampires are no fun to haunt/ Oh, but Edward, you can bite me if you want" — "Cedric," by the Moaning Myrtles

[article id="1590892"]Robert Pattinson[/article] isn't the only thing that "Harry Potter" and "Twilight" share. Thanks to [article id="1561855"]wizard rock[/article], other fandoms have gotten the idea: If you really want to spread your love of a book or movie, form a band in tribute to it.

"We wanted to play music that you wouldn't normally see on the TV or the radio," Harry and the Potters singer/keyboardist Joe DeGeorge said. "We weren't thinking we would create a wizard-rock movement. It just evolved."

The 500-and-counting wizard-rock bands, who play clubs, libraries, music fests and "Harry Potter" conventions, have not only created a movement of their own, but they've acted as godfathers to a new one: "Twilight" rock, or Twi-rock. ("Why aren't they calling it vampire rock?" DeGeorge asked. "But it's cool to see 'bands about books' realized in some way.")

(Wizard-rock and Twi-rock bands are paving the way for more movie-based music — read more in the MTV Movies Blog!)

Twi-rock, still in its infancy, only has a handful of bands to its name, from [article id="1590533"]the Bella Cullen Project[/article] to Bella Rocks to the Mitch Hansen Band. One wizard-rock band, the Owl Post, even has a spin-off, called Be Safe Bella. But there are some growing pains.

Even though it's possible to be a fan of both book series — and a member of both music scenes — there's definitely tension between the two (which has only worsened with last week's news that the [article id="1592949"]"Harry Potter and the Half-Blood Prince" movie would be bumped to a July 2009 release date, leaving November 21 open for "Twilight"[/article]).

"There's a backlash in the 'Harry Potter' community," said Owl Post/ Be Safe Bella's Devin Overman. "Some people don't like 'Twilight' potentially becoming the new 'Harry Potter.' There's a lot of groaning and moaning about the movie coming out. And the fact that there is 'Twilight' music kind of bothers some people."

When a question was posed about Twi-rock during a wizard-rock panel at the Harry Potter Terminus convention earlier this month, the audience booed. And when Matt Maggiacomo from the Whomping Willows responded to the Twi-rock question with "Do they sound like Hannah Montana?" the audience cheered.

" 'Twilight' is sort of like the 'Hannah Montana' of literature," the Remus Lupins' Alex Carpenter explained to MTV News. "If you're outside the 14-to-16-year-old age range, you might listen to it, and it might get stuck in your head, but it's not good literature. It's not really enriching your life the way 'Harry Potter' might."

Plus, many wizard rockers argue, there are aspects of "Harry Potter" that lend themselves more to making rock music than "Twilight" does — from the DIY aesthetic to the sense of community to the depth of characters and themes explored.

"People have been writing about love for eons," said Amy Snow of the wizard-rock band Romilda Vane and the Chocolate Cauldrons. "Love is never going to get old, and if you can find new ways to talk about love, you can find new ways to write about 'Twilight.' But I don't think 'Twilight' is as powerful as 'Harry Potter' is. 'Twilight' is about love and being a teenager and wondering if you fit in, and 'Harry Potter' is that and so much more."

"It's different for us," said Lauren Fairweather of the Moaning Myrtles. "For us, it's a community, not so much a genre of music. And I don't know if they have a community yet, if they all get together, if the bands are as close as all of us are."

"There isn't a whole lot of that in 'Twilight,' " Carpenter said. "There's just a lot of romance and biting."

But even if "Twilight" is taking a bite out of the "Harry Potter" scene, some of the wizard-rock bands welcome the fresh blood and say — even if it might be ill-advised when dealing with vampires — "Come on in."

"I don't think it could have a movement on its own," said Kristina Horner of the wizard-rock band the Parselmouths (they reference "Twilight" in their song "This Is Never Going to End"). "But wizard rock can expand to be bands themed about other books. It doesn't just have to be about 'Harry Potter.' Anyone who is singing about any book can be part of wizard rock."

"If you're a male 'Twilight' fan, I highly recommend starting a band named Edward and the Cullens," said Ministry of Magic's Aaron Nordyke. "Every teenage girl in America will love you."

Check out everything we've got on "Harry Potter and the Half-Blood Prince" and "Twilight."

For breaking news, celebrity columns, humor and more — updated around the clock — visit MTVMoviesBlog.com.