If you're unfamiliar with WebQuests, read this introduction first.
Vampires have been all the rage in fiction for the past couple decades. As different authors and film-makers have made their own stories, many have made changes to the classic lore. What vampires look like, what they can do, and what their limitations are vary from one story to the next.
Your students have 3 tasks. Either individually or in pairs, they need to conduct research through the internet, then write out their conclusions.
1. The Origin of Vampires
How did Vampire lore begin?
What were the first vampire stories?
How were the original vampires described?
2. Vampire vs. Vampire
Compare and Contrast at least three versions of vampires. Students will likely be more interested in the most modern versions, but encourage them to choose one classic version as well. Here are some versions to consider, although you could certainly find more:
Bram Stoker's Dracula
Richard Matheson's I Am Legend
Anne Rice's The Vampire Chronicles
Buffy the Vampire Slayer
Marvel Comic's Blade
The Twilight Saga
3. The Ultimate Vampire
Students should take different aspects of vampire legends they've researched to form their own vampire legend (they can't just duplicate their favorite version and be done with it; it needs to be different somehow). Should vampires be feared, pitied, or loved? What kills them? How human do they appear? What are their abilities? Students decide for themselves the best combination of answers to these questions and plenty more, taking into account everything they've researched.
Many versions of vampire lore are not suitable for younger students, whether it's because of the horror aspect or sexual content or something else. Before assigning this project, decide which sources you might encourage students to read or watch, which sources you want them to research indirectly (without reading or watching the source itself; just reading an article about it, perhaps), and which sources you want them to outright avoid.