Degenerate Vampire Weaknesses. The vampire has the following flaws:

Silver Blow to the Head. If a silvered stake is driven into the vampire's head while the vampire is incapacitated in its resting place, the vampire is stunned until the stake is removed.

Sunlight Hypersensitivity. The vampire takes 40 radiant damage when it starts its turn in sunlight. While in sunlight, it has disadvantage on attack rolls, ability checks, and saving throws.

Enraged. When the vampire possesses less than half of its maximum hit points or is exposed to sunlight, it becomes enraged so long as either condition remains true. While enraged, the vampire's movement speed is doubled and its Multiattack allows it to make three attacks instead of just two.

Keen Hearing and Smell. The vampire has advantage on Wisdom (Perception) checks that rely on hearing or smell.

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

Shapechanger. If the vampire isn't in sunlight, it can use its action to polymorph into a Medium swarm of bats or an ownerless shadow, or back into its true form.

While in swarm of bats 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 shadow form, the vampire can't take any actions, speak, or manipulate objects. It gains a +3 bonus to its Stealth skill, 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 shadow can do so without squeezing. 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.

Regeneration. The vampire regains 30 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight. If the vampire takes radiant damage, this trait instead only restores 5 hit points at the start of the vampire's next turn.

Shadowy Escape. When it drops to 0 hit points outside its resting place, the vampire transforms into a shadow (as in the Shapechanger trait) instead of falling unconscious, provided that it isn't in sunlight. If it can't transform, it is destroyed.

While it has 0 hit points in shadow form, it can't revert to its vampire form, and it must reach its resting place within 2 hours or be destroyed. Once in its resting place, it reverts to its vampire form. It is then incapacitated until it regains at least 1 hit point. After spending 1 hour in its resting place with 0 hit points, it regains 1 hit point.

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

Trampling Charge. If the vampire moves at least 20 feet straight toward a creature and then hits it with a gore attack on the same turn, that target must succeed on a DC 18 Strength saving throw or be knocked prone. If the target is prone, the vampire can make one bite attack against it as a bonus action.

Tunneler. The vampire can burrow through solid rock at half its burrow speed and leaves a 5-foot-diameter tunnel in its wake.