Multiattack

The dune mimic makes four pseudopod attacks.

Pseudopod

Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage. If the dune mimic is in object or terrain form, the target is subjected to the mimic's Adhesive trait.

Engulf

The dune mimic engulfs all creatures it has grappled. An engulfed creature can't breathe, is restrained, is no longer grappled, has total cover against attacks and other effects outside the dune mimic, and takes 18 (4d8) acid damage at the start of each of the dune mimic's turns. When the dune mimic moves, the engulfed creature moves with it. An engulfed creature can try to escape by taking an action to make a DC 15 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the dune mimic.