Holdover ‘Oppenheimer’ also remains a force of nature as it zeroes in on $400 million globally.

Sword-wielding smiling turtles and a sharp-toothed shark open at the box office this weekend in the shadow of Barbenheimer.

Barbie cleared the $400 million mark at the domestic box office on Thursday, its 14th day in release (that’s the fastest ever for a Warner Bros. movie). Globally, Barbie has now amassed north of $900 million in ticket sales, and will join the billion-dollar club by Sunday or early next week. It easily stayed No. 1 Thursday with another $11.8 million.

Universal’s Oppenheimer also remains a force of nature as it closes in on $500 million globally. In North America, it hit $200 million on Thursday after earning another $5.6 million for the day for a second-place finish.

There are two new nationwide offerings this weekend: Paramount’s Teenage Mutant Ninja Turtles: Mutant Mayhem and New Line/Warner Bros.’ shark pic Meg 2: The Trench.

The TMNT reboot, which opened Wednesday, earned $4.9 million Wednesday for a two-day total of $15.1 million, including $3.9 million in Tuesday evening previews. The PG family pic is looking at a five-day debut in the $35 million range, but that could shift as the weekend unfolds.

Meg 2, opening everywhere on Friday, earned $4 million in Thursday previews. It is tracking for a $25 million to $30 million opening.

More to come.

BY PAMELA MCCLINTOCK