Vampiric Giant Snake

Legendary Resistance (3/Day). If the Vampiric Giant Poisonous Snake fails a saving throw, it can choose to succeed instead.

Regeneration. The Vampiric Giant Poisonous Snake regains 20 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight or running water. If the vampire takes radiant damage or damage from holy water, this trait doesn't function at the start of the vampire's next turn.

Vampire Weaknesses. The Vampiric Giant Poisonous Snake has the following flaws:

Forbiddance. The Vampiric Giant Poisonous Snake can't enter a residence without an invitation from one of the occupants.

Stake to the Heart. If a piercing weapon made of wood is driven into the Vampiric Giant Poisonous Snake's heart while the Vampiric Giant Poisonous Snake is unconscious, the Vampiric Giant Poisonous Snake is paralyzed until the stake is removed.

Sunlight Hypersensitivity. The Vampiric Giant Poisonous Snake takes 20 radiant damage when it starts its turn in sunlight. While in sunlight, it has disadvantage on attack rolls and ability checks.

Bite. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 13 (3d6 + 4) piercing damage, and the target must make a DC 14 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one. If the target creature is constricted by the Vampiric Giant Snake, the target takes 10 (3d6) necrotic damage instead. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the Vampiric Giant Snake regains hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0. A humanoid slain in this way and then buried in the ground rises the following night as a vampire spawn under the vampire's control.

Constrict. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 13 (2d8 + 4) bludgeoning damage, and the target is grappled (escape DC 16). Until this grapple ends, the creature is restrained, and the snake can't constrict another target.

Gaze (Recharge 5-6). The Vampiric Giant Snake casts Dominate Person on a creature it can see within range if the creature is not averting its gaze. It requires a DC 15 Wisdom Saving Throw.

The Vampiric Giant Snake can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The vampire regains spent legendary actions at the start of its turn.

Move. The Vampiric Giant Snake moves up to its speed without provoking opportunity attacks.

Bite. The Vampiric Giant Snake makes one bite attack.

Constrict (Costs 2 Actions). The Vampiric Giant Snake makes one constrict attack.

Gaze (Costs 3 Actions). The Vampiric Giant Snake makes one attempt to dominate a creature it can see within range.