Young Hercules (1998)

Season 1: Episode 43

Hercules, Iolaus, Lilith, Theseus, and fellow cadet Marco find themselves trapped in a large area of sand known as the Dune Sea. It's known as forbidden, and for a reason too, since it is inhabited by sand sharks who hunt anyone foolish enough to enter the area. Of the five cadets who entered, one will not leave.