In her career, Blake Lively had to deal with terrors ranging from Blair Waldorf at her most vindictive to a really lame superhero played by the man who would eventually become her husband. However, in her upcoming movie she'll go up against an ocean-dwelling horror. The Shallows stars Lively as a woman who is attacked by a shark, and then marooned on a rock. The shore is in sight, but the shark is on the prowl. The movie's tagline is: "What was once in the deep, is now in the shallows." Ominous. The teaser trailer, released today, is as tense as one might expect given the subject matter. It features some petrified cries for help from Lively, and some menacing shark's eye view shots.Let's just hope Lively's character, Nancy, doesn't end up as dead as Preserve . Perhaps Nancy prevails and ends up selling shark teeth necklaces on a lifestyle website.While the movie does look serious, despite our jokes, Lively has posted some goofy pictures from the set on Instagram. The movie is out June 24.