Sandworm (Final Fantasy V)

The Sandworm is a boss in Final Fantasy V. It attacks the party when they try to cross the Desert of Shifting Sands. Upon its defeat, they are able to use its body as a bridge to enter the desert.

Strategy
The Sandworm will hide during the battle in one of three holes. Wait for the worm to pop up, then hit him with all your best attacks. Attacking him with magic is not recommended, since he'll counter with Gravity, halving the character's HP. He'll also use Gravity if you target an empty hole. His other attack is Quicksand, which inflicts sap on the target.

A very easy way to win this battle is to use the Blue Magic Aqua Breath. Since the worm is a desert type enemy, Aqua Breath will do 8x damage, inflicting 3000-4000 damage, easily killing the worm in one hit.