Tunneler. The Sand Worm can burrow through solid rock at half its burrow speed and leaves a 5-foot-diameter tunnel in its wake. 

Siege Monster. The Sand Worm deals double damage to objects and structures.

Stone Camouflage. The Sand Worm has advantage on Dexterity (Stealth) checks made to hide in  rocky and sandy terrain. 

Bite. Melee Weapon Attack: +11 to hit, reach 10 ft., 1 target. Hit: 19 (2d10 + 4) piercing damage. If the target is a Large or smaller creature, it must make a DC 15 Dexterity Saving Throw or be swallowed by the worm. A swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside of the worm, and it takes 21 (3d6) acid damage at the start of the worms turns. If the worm takes 30 or more damage from a single turn from a creature inside it, the worm must succeed a DC 18 Constitution saving throw or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the worm. If the worm dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone. 

Acid Spit. The Sand Worm spits a burning acid in a 30 ft cone. All creatures inside this cone must make a DEX saving throw (DC 15) or take 36 (5d6) acid damage and be Blinded for 1 minute. Targets affected by the Blinded condition can make a CON saving throw at the start of their turns.