LOS ANGELES - The shape-shifting robots of "Transformers" have taken on a new form: Huge piles of cash.

The sci-fi saga "Transformers," DreamWorks and Paramount's big-screen take on the Hasbro toys, debuted with $67.6 million in ticket sales in its first weekend, according to studio estimates Sunday. That gave it $152.5 million since opening with preview screenings Monday night.

If the weekend figures hold when final numbers are released Monday, that would give "Transformers" the biggest first week revenues ever for a non-sequel, surpassing the $151.6 million of 2002's "Spider-Man." But factoring in today's higher ticket prices, "Spider-Man" drew more people in its first week, about 26.1 million, compared to 22.5 million for "Transformers."

"Transformers," was directed by Michael Bay and features a cast led by Shia LaBeouf and Megan Fox, who are among the humans hurled into the action when two races of warring robots bring their feud to Earth.

The movie's striking visual effects and the Transformers brand — which debuted in the 1980s with toys, a TV show and an animated movie — proved irresistible for audiences, said Rob Moore, Paramount's head of worldwide marketing and distribution.

"Michael Bay created something visually that people hadn't seen before," Moore said. "When you look at a jet plane flying under a bridge then flipping and turning into a robot, those kinds of images people found incredibly unique and compelling."

"Transformers" also took in $93.6 million in 23 other countries where it has opened since June 28.

However, the overall domestic box office plunged. The top 12 movies took in $161.5 million, down 23 percent from the same weekend last year, when "Pirates of the Caribbean: Dead Man's Chest" opened with what was then a record weekend of $135.6 million.

"The good news is we've got another big one right around the corner with 'Harry Potter,'" said Paul Dergarabedian, president of box-office tracker Media By Numbers. "We should be looking at a strong midsummer boost that'll hopefully carry through to the end of summer."

The weekend's other new wide release, the Warner Bros. comedy "License to Wed," took fourth place with $10.4 million, raising its total since debuting Tuesday to $17.8 million. It stars Robin Williams as a minister who forces an engaged couple (Mandy Moore and John Krasinski) through a tortuous marital boot camp.

The previous weekend's No. 1 flick, Disney's animated "Ratatouille," dropped to second place with $29 million, raising its 10-day total to $109.5 million. "Ratatouille" held up well in its second weekend as revenues fell just 38 percent, compared to drops of 50 percent or more for many other big summer movies.

Disney's "Pirates of the Caribbean: At World's End" took in $3 million to climb to $301.7 million domestically, following Sony's "Spider-Man 3" and DreamWorks Animation's "Shrek the Third" as $300 million hits this year.

In limited release, MGM's "Rescue Dawn" debuted strongly with $104,000 in six theaters. It stars Christian Bale in the real-life story of a U.S. pilot struggling to survive after he's shot down over Laos during the Vietnam War.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Media By Numbers LLC. Final figures will be released Monday.

1. "Transformers," $67.6 million.

2. "Ratatouille," $29 million.

3. "Live Free or Die Hard," $17.4 million.

4. "License to Wed," $10.4 million.

5. "Evan Almighty," $8.1 million.

6. "1408," $7.1 million.

7. "Knocked Up," $5.2 million.

8. "Fantastic Four: Rise of the Silver Surfer," $4.15 million.

9. "Sicko," $3.65 million.

10. "Ocean's Thirteen," $3.5 million.