This is a strange and atmospheric sci-fi/horror movie about a biologist named Lena (Natalie Portman) who goes on a classified government expedition with four other female scientists into a mysterious environmental disaster zone, hoping to find her husband who disappeared there a year earlier. Inside the zone, natural laws don't seem to apply and nothing seems to make sense. (This could describe the entire movie.)

After they get inside the zone, the group encounters a gigantic mutated white alligator with teeth growing all over the inside of its mouth. It grabs one woman by the backpack, which saves her, then it swims over to the group and attacks them. The women shoot at it but it doesn't stop until Lena unloads her automatic rifle into the gator's head which finally kills it. Then she turns biologist, poking and prodding it. There's a nice shot from inside the alligator's mouth, and the gator effect is nicely done, but the whole scene only serves to show us that there are some very bizzare and dangerous things inside the zone.

Watch the gator attack scene on YouTube.