This ability allows you to transform into a bat, mist, wolf and cow. For bat and mist see vampire sheet (pg. 297 MM), for wolf, you have a 40 foot walking speed, with a bite that has +4 to hit, +4 to damage on 1d8. For cow, you have a walking speed of 35, and +4 to hit and damage on 1d12

As this race, you get a +3 to Strength, constitution and dexterity 

You get a 120 feet radius dark vision

Once a day, you can summon 2d4 bats or rat, or if your outside, you can summon 3d6 wolves. They arrive in 1d4 rounds and stays for 1 hour,  obeying the vampire

During combat, you can completely let go of your vampire side, as if entering range, your attacks and health double temporarily, but you take double damage.

If you can see a creature within 30 feet, you can bonus action charm it. The creature has to succeed on a DC 17 wisdom check or be charmed

You transform into your true vampire form, gaining new abilities. You gain multi attack, two claws which has a +9 to hit and can allow you to grapple with a dc 18. and rolls 1d8+4, and a bite, which has +9 to hit and 1d6+4, and if grappled or restrained, deals 3d6 necrotic damage, and you gain the same amount of temp hit points as the necrotic damage. If the target dies and is buried, they rise as a vampire spawn

You take 20 damage in running water, paralyzed by a stake to the heart while prone, and double fire damage