Amorphous. The sarcophagus slime can move through a space as narrow as 1 inch wide without squeezing.
Multiattack. The sarcophagus slime uses its Frightful Presence, uses its Corrupting Gaze, and makes two slam attacks. Slam. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (2d6 + 2) bludgeoning damage plus 14 4d6 acid damage. Frightful Presence. Each creature of the sarcophagus slime’s choice that is within 60 feet of the sarcophagus slime and aware of it must succeed on a DC 15 Wisdom saving throw or become frightened for 1 minute. A frightened creature repeats the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the sarcophagus slime’s Frightful Presence for the next 24 hours. Corrupting Gaze. The sarcophagus slime targets one creature it can see within 30 feet of it. If the target can see the sarcophagus slime, the target must succeed on a DC 15 Constitution saving throw or take 14 (4d6) necrotic damage and its hit point maximum is reduced by an amount equal to the necrotic damage taken. If this effect reduces a creature’s hit point maximum to 0, the creature dies and its corpse becomes a sarcophagus slime within 24 hours. This reduction lasts until the creature finishes a long rest or until it is affected by greater restoration or comparable magic.