[movie id="369059"]"Transformers: Revenge of the Fallen"[/movie] has made the biggest splash at this year's box office as the only film to cross the $400 million mark domestically. But if we're talking about pure profit, the big story is the [article id="1624679"]indie-turned-weekend-champ "Paranormal Activity,"[/article] which cost about $15,000 to make and raked in $22 million from Friday through Sunday.

That weekend success brought the horror film's total gross to more than $65 million, making it the single most profitable film in history, according to some number-crunching at TheWrap.com. Comparing the "Paranormal" production budget to its global box-office haul, the site found that the film has delivered a staggering 434,000 percent return on investment. That number will only grow in the coming weeks, considering the film only just received a wide release, moving up from 950 theaters to almost 2,000 last weekend.

The next closest competitor is 1999's "The Blair Witch Project," another indie horror flick. With a production budget of $60,000, that movie posted a 414,000 percent ROI. After two pre-Depression-era films, "ET: The Extraterrestrial" delivered the fifth highest percentage, a comparatively small return of 7,000 percent.

"[T]his movie is probably more important than one that does $300 million or $400 million," Don Harris, executive VP of distribution for Paramount, which released "Paranormal," told TheWrap.

Unsurprisingly, the studio is looking into bringing [article id="1624815"]more "Paranormal"[/article] to the big screen. "We have the rights on a worldwide basis to do 'Paranormal 2,' and we're looking to see if that makes some sense," Paramount chairman Brad Grey told the Los Angeles Times. "No one expected it to do this well this quickly. Our heads are spinning."

Check out everything we've got on "Paranormal Activity."

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