Lindwurm

Ice Walk. The lindwurm can move across icy surfaces without needing to make an ability check. Additionally, difficult terrain composed of ice or snow doesn't cost it extra movement.

Sure-Footed Skater. While the lindwurm is on snow or ice, it has advantage on Strength and Dexterity saving throws made against effects that would knock it prone.

Multiattack. The lindwurm makes one Bite attack and two Claw attacks. It can replace its Bite attack with one Constrict attack.

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 5) piercing damage. If the target is a creature, it must succeed on a DC 15 Constitution saving throw or contract a disease and be poisoned until the disease is cured. At the end of each long rest, the diseased creature must repeat the saving throw. On a failure, the creature suffers one level of exhaustion and doesn't regain expended Hit Dice from the rest. On a success, the creature's exhaustion level decreases by one, and it regains expended Hit Dice as normal from the rest. If a successful saving throw reduces the diseased creature's level of exhaustion below 1, the creature recovers from the disease, ending it.

Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage.

Constrict. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage, and the target is grappled (escape DC 15). Until this grapple ends, the target is restrained, and the lindwurm can't Constrict another target.