Coldlight Charger

Charge. If the charger moves at least 20 feet straight toward a target and then hits it with an antlers attack on the same turn, the target takes an extra 9 (2d8) bludgeoning damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone.

Sure-Footed. The charger has advantage on Strength and Dexterity saving throws made against effects that would knock it prone.

Blinding Light. The charger sheds bright light in a 20-foot radius and dim light for an additional 20 feet. As a bonus action, the charger can target one creature in its bright light that it can see and force it to succeed on a DC 15 Constitution saving throw or be blinded until the start of the charger’s next turn.

Icy Doom. Any creature killed by the charger freezes for 9 days, during which time it can’t be thawed, harmed by fire, animated, or raised from the dead.

Unusual Nature. The charger doesn’t require air, food, drink, or sleep.

Multiattack. The charger fires its Cold Beam, it then makes two attacks: one with its antlers and one with its hooves.

Coldlight Antlers. Melee Weapon Attack: +8 to hit, reach 5 ft., one target, Hit: 8 (1d8+5) piercing damage plus 10 (3d6) cold damage.

Hooves. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 10 (2d4 + 5) bludgeoning damage.

Cold Beam. The charger fires an icy blast in a 45-foot line. Each creature in that area must make a DC 15 Constitution saving throw, taking 25 (4d10+3) cold damage and having their speed reduced by 10 ft. until the end of their next turn on a failed save, or half as much damage and with no speed reduction on a successful one.