Why Has 'Sharknado' Become Such a Culture Phenomenon?

— -- “Sharknado” is the movie with the most unlikely plot in history -- a tornado scooping man-eating sharks out of the ocean and dumping them on Los Angeles.

Even more unlikely, was the cult following that developed for this SyFy made-for-TV movie. It was so successful, the filmmakers made a sequel: “Sharknado 2.” Same thing happens -- only this time in New York City.

Grab Your Chainsaws! 'Sharknado 2' Takes NYC

The 7 Most Unrealistic Moments From the 'Sharknado 2' Trailer

Actress and model Tara Reid is back and said that she thinks the second one is better than the first.

“This film is amazing,” Reid told ABC's "Nightline." “We realized, here’s a formula. It worked on the first one, so we don’t want to mess with that one."

Actor Ian Ziering is also back as the leading man, with his most famous prop in hand.

“Of course, you got to bring the chainsaw back,” said director Anthony C. Ferrante. “But what he does with it, I think, is what's going to be the fun part.”

The first movie -- so bad that it’s good -- was a social media smash hit, generating 5,000 tweets per minute.

"Social media is almost the reason for the existence for a movie like this," said Time magazine pop culture writer James Poniewozik.

When the original aired, Judah Freedlander, who played writer Frank Rossitano on the TV series “30 Rock,” falsely took credit on Twitter for directing it, so he is one of the cameos in the sequel.

Other cameos include Kelly Osbourne, Mark McGrath of the band Sugar Ray and Billy Ray Cyrus.

“[Cyrus] plays a doctor,” Ferrante said.

Celebrities were lining up to take part in the sequel. But when “Sharknado” filmmakers were working on the first film, they had to lie to get anyone involved.

“In the beginning, it was called ‘Dark Skies,’ so I thought, 'OK, that doesn’t sound so bad,' and then three days into the movie, they start calling it ‘Sharknado,’” Reid said. “I’m like, ‘we can’t call it ‘Sharknado,’ it’s going to look horrible on my resume. I’m going to never work again.’”

“And I said, ‘look, trust me, if they call it ‘Sharknado’ it’s going to be a good thing,’” Ferrante said.

Turns out, he was right.

“When the movie came out I was actually in Mexico and the next day I was on a plane back to LA and the stewardess came up to me ... and said, ‘I love ‘Sharknado,’” and I thought, ‘What?’ I literally was like, ‘What are you talking about?’” Ried said. “It got me out of just being the girl from ‘American Pie’ and now it’s ‘Sharknado.’”

“Sharknado 2” premieres tonight on the SyFy Channel at 9 p.m. ET, and in 90 countries, and “Sharknado 3” is already in the pipeline.

ABC's Nick Watt contributed to this report