Contractual Boss Immunity: Unlike the vanilla worm bosses, the Desert Scourge reduces the damage of piercing weapons with every segment they pierce, which massively reduces the damage they would normally cause to it - a trait shared by a number of the Calamity worms and the Revengeance/Death Mode versions of the vanilla worms, but more noticeable considering its earlygame status.
Art Evolution: It went from a blue worm into a drier-looking brown worm, which looks more terrifying than its old sprite.
Killing it enables sandstorms and also allows the blocks in the Sunken Sea to be mined, allowing true access into the biome. The Desert Scourge drops various water-themed weaponry/equipment, and gives all the ingredients required to make Victide Bars, an early crafting material required to make beginner-level equipment. It's the first Calamity-exclusive boss available when you start the game, and has to be fought in the Desert. Once a mighty ocean worm that destroyed the Ocean Kingdom, its home has been dried up by Calamitas and it has been forced to become a desert worm.