They wanted to call it Lake Placid but that was taken

During the death of a scuba diver on Black Lake it is discovered that the lake in Maine is home to a 30 foot crocodile that somehow migrated from Asia. The local police, sheriff Hank Keough (Brendan Gleeson), paleontologist Kelly Scott (Bridget Fonda), a crocodile worshiper, Hector Cyr (Oliver Platt), and a fish and game officer Jack Wells (Bill Pullman) must work together to rid the remote lake of the terror before it kills again.

Unbeknownst to them a cranky old lady Mrs. Delores Bickerman (Betty White) has been feeding cows to the monster. To her it is a pet that lives in the lake. Not satisfied with just cows the crocodile works its way through deputies, moose, bear and helicopters. Whatever comes along.

"Lake Placid" was released in 1999 and was directed by Steve Miner.

“Lake Placid” is the first in the Lake Placid franchise. As such it is probably the best. The main actors are Bill Pullman, Bridget Fonda, Oliver Platt, Brendan Gleeson and last but absolutely not least Betty White. All seasoned professions. The script is tight with banter back and forth between the actors. Characterization is well rounded. Special effects are done brilliantly by Stan Winston. Everything comes together to create a modern classic that is both funny and scary. It’s exciting, full of action and yes dear, it does have a big monster.

The Visitors Center on Main Street, Lake Placid, Adirondacks USA receives questions on a weekly basis via phone, email and even in person by those asking if there are really crocodiles in Lake Placid. People also want to know where they can go to see them. The visitor's center has been answering that question since 1999, when the first movie named "Lake Placid" was released.