Baron Von Bats

Shapechanger. If the vampire isn't in sunlight or running water, it can use its action to polymorph into a Tiny bat or a Medium cloud of mist, or back into its true form.

While in bat form, the vampire can't speak, its walking speed is 5 feet, and it has a flying speed of 30 feet. Its statistics, other than its size and speed, are unchanged. Anything it is wearing transforms with it, but nothing it is carrying does. It reverts to its true form if it dies.

While in mist form, the vampire can't take any actions, speak, or manipulate objects. It is weightless, has a flying speed of 20 feet, can hover, and can enter a hostile creature's space and stop there. In addition, if air can pass through a space, the mist can do so without squeezing, and it can’t pass through water. It has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage, except the damage it takes from sunlight.

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

Spider Climb. The vampire can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Vampire Weaknesses. The vampire has the following flaws:

Harmed by Running Water. The vampire takes 20 acid damage if it ends its turn in running water.

Stake to the Heart. If a piercing weapon made of wood is driven into the vampire's heart while the vampire is incapacitated in its resting place, the vampire is paralyzed until the stake is removed.

Multiattack. (Vampire Form Only). The vampire makes two attacks, only one of which can be a bite attack.

Bat Staff (Vampire Form Only). Melee Weapon Attack: +9 to hit, reach 5 ft., one creature. Hit: 14 (3d6 + 4) bludgeoning damage.

Bite. (Bat or Vampire Form Only). Melee Weapon Attack: +9 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire, incapacitated, or restrained. Hit: 6 (1d4 + 4) piercing damage plus 10 (4d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampire 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.

Beam of Bats (recharge 4 rounds). The vampire targets one person it can see within 60 ft of it and the target must make a dexterity saving throw DC: 19, on a fail the target takes 60 (8d8 + 20) necrotic damage, and nothing on a successful save, The vampire heals half the damage done if any, also the target is cursed that on every round of combat until the target takes lighting or radiant damage they are surrounded by tiny bats that have a +8 to hit, Hit: 10 (3d4 + 4) piercing damage, the vampire heals half of the damage taken if any.

Call of the Bats (1/Day). The vampire magically calls 1d4 Vampire spawn, provided that the sun isn't up. While outdoors, the vampire can call 1d8 Vampire spawn instead. The called creatures arrive in 1d2 rounds, acting as allies of the vampire and obeying its spoken commands. The beasts remain for 1 hour, until the vampire dies, or until the vampire dismisses them as a bonus action.

The vampire 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.

Bat call. The vampire summons a Swarm of bats.

Bats staff. The vampire makes one Bats Staff attack.

Bite.(Costs 2 Actions). The vampire makes one bite attack.