Vampiric Gibbering Mouther

Aberrant Ground. The ground in a 10-foot radius around the mouther is doughlike difficult terrain. Each creature that starts its turn in that area must succeed on a DC 10 Strength saving throw or have its speed reduced to 0 until the start of its next turn.

Gibbering. The mouther babbles incoherently while it can see any creature and isn't incapacitated. Each creature that starts its turn within 20 feet of the mouther and can hear the gibbering must succeed on a DC 10 Wisdom saving throw. On a failure, the creature can't take reactions until the start of its next turn and rolls a d8 to determine what it does during its turn. On a 1 to 4, the creature does nothing. On a 5 or 6, the creature takes no action or bonus action and uses all its movement to move in a randomly determined direction. On a 7 or 8, the creature makes a melee attack against a randomly determined creature within its reach or does nothing if it can't make such an attack.

Regeneration. The vampire regains 10 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.

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:

Forbiddance. The vampire can't enter a residence without an invitation from one of the occupants.

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

Stake to the Heart. The vampire is destroyed if a piercing weapon made of wood is driven into its heart while it is incapacitated in its resting place.

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

Multiattack. The gibbering mouther makes one bite attack and, if it can, uses its Blinding Spittle.

Bite. Melee Weapon Attack: +2 to hit, reach 5 ft., one creature. Hit: 17 (5d6) piercing damage plus 17 (5d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampiric gibbering mouther 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. If the target is Medium or smaller, it must also succeed on a DC 12 Strength saving throw or be knocked prone. If the target is killed by this damage, it is absorbed into the mouther.

Blinding Spittle (Recharge 5–6). The mouther spits a chemical glob at a point it can see within 15 feet of it. The glob explodes in a blinding flash of light on impact. Each creature within 5 feet of the flash must succeed on a DC 15 Dexterity saving throw or be blinded until the end of the mouther's next turn.