Coldspawned Mummy

Multiattack. The mummy can use its Chilling Glare and make one Icy Grasp

Icy Grasp. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 9 (2d6 + 2) bludgeoning damage plus 7 (2d6) cold damage. If the target is a creature, it must succeed on a DC 12 Constitution saving throw or be cursed with the mummy's freezing curse. The target's speed is halved while the target is cursed, which lasts until removed by the remove curse spell or other magic.

Chilling Glare. The mummy targets one creature it can see within 60 feet of it who's speed is halved, either by a mummy's freezing curse or by Vandomar's freezing blast. That creature must succeed on a DC 11 Wisdom saving throw or be restrained until the end of the mummy's next turn, as they feel as if they are frozen solid. If the target fails the saving throw by 5 or more, it is also paralyzed for the same duration.