Last week Twitter went crazy over a SyFy Channel made-for-TV movie called "Sharknado."

The film was made by a small studio known as The Asylum.

Known for making extremely campy science-fiction and horror films involving monsters and aliens, the studio also makes knock-offs of blockbuster films, or "mockbusters," for companies like Redbox and Netflix.

Due to the way movies are released after they're in theaters, Redbox and Netflix aren't able to add them to their selections right away. To capitalize on the release of blockbusters while they're still fresh in the public's minds, the companies will order one of Asylum's similar-sounding movies in the hopes that people will be fooled.

These movies aren't just inspired by similar films. They often have titles that border on copyright infringement and are marketed with posters close enough to the original big-budget films that those who don't follow movie releases closely can be tricked into renting or downloading them.