Vitriolic Wurm (5e Creature)
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Huge dragon, chaotic evil
Saving Throws Str +13, Con +13, Wis +7
Amphibious. The wurm can breathe air and water.
Tunneler. The wurm can burrow through solid rock at half its burrow speed and leaves a 10-foot-diameter tunnel in its wake.
Multiattack. The wurm can use its Acid Spurt up to 3 times. It than makes a bite attack or uses its Swallow.
Acid Spurt. The wurm sprays acid at a target within 20 feet of it. The target must make a DC 21 Dexterity saving throw, taking 10 (3d6) acid damage on a failed save or half as much damage on a successful one.
Bite. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 24 (3d10 + 8) piercing damage. If the target is a creature, it is grappled (escape DC 18). Until the grapple ends, the target is restrained and the wurm can't make bite attacks against other targets.
Swallow. The wurm makes one bite attack against a Medium or smaller target it is grappling. If the attack hits, the target is also swallowed, and the grapple ends. While swallowed, the target is blinded and restrained, it has total cover against attacks and other effects outside the wurm, and it takes 33 (6d10) acid damage at the start of each of the wurm's turns. A wurm can have only one creature swallowed at a time.
The ebony black vitriolic wurms lurk beneath the mud and peat of bogs and swamps, traversing stagnant waters buzzing with insects and overgrown with aquatic plants. Their tunnels often cross into sunken caves and underground rivers.