Creature Unknown

From the Amazon's forbidden depths came the Creature from the Black Lagoon.

When a group of old friends decide to camp out in the same woods where one of their pals was killed four years earlier, their weekend reunion turns grisly once more as a mysterious creature begins to haunt them -- and hunt them down. At the advice of a geneticist, the campers attempt to leave the forest, but it may be too late; the murderous being seems hell-bent on destruction, no matter what the cost.