The man who created the crocodile for the film was none other than Stan Winston. Winston was also the creator of the monsters in Aliens (1986) and Jurassic Park (1993).
The crocodile as CGI or animatronic has about 3 minutes and 43 seconds of screentime.
Filming of the movie had to be postponed due to poor weather conditions. Director Steve Miner took on directing duties for Halloween H2O while he was waiting to shoot Lake Placid.
The largest crocodile in captivity was Lolong who measured 6.17m (20ft 3in) when he died from pneumonia in February 2013 in the Phillipines. The crocodile depicted in the movie is about 10 feet longer.
Stan Winston and his crew realized Lake Placid's crocodile as a full-size animatronic puppet -- complete with moving head and tail and snapping jaws -- that would function underwater.