Looking forward to an upcoming beach vacation? The final trailer for “The Shallows” may make you reconsider cooling off in the water.

Blake Lively leaves her designer “Gossip Girl” dresses behind to play a surfer in the thriller. This newly released trailer is under two minutes long but manages to inspire immense dread. We witness Lively’s character, Nancy, suffer a brutal injury when she’s overcome by a wave. And that’s just the beginning of this horror story. Nancy, who set out on the waters alone, has found company: a humongous, decidedly unfriendly looking great white shark.

The footage is accompanied by a voice-over extolling the virtues of self-reliance as menacing dubstep plays. The dialogue, score, and visuals make for a terrifying combination.

Nancy is injured, and stranded on a rock hundreds of yards away from shore. It looks like she’ll have to get by the shark — somehow, someway — to return to land. But the surprise twist ending to the trailer hints that Nancy’s journey may be even more complicated, and harrowing, than what we’ve caught glimpses of.

It looks as though “The Age of Adaline” star will really be carrying this movie with her toothy CGI co-star. Of her demanding role, Lively told Entertainment Weekly, “It was terrifying and one of the most vulnerable things you can do but you gotta do it, right?”

“The Shallows” hits theaters June 29.