Your Intelligence score increases by 1, and your Charisma score increases by 2.

Babadooks are born when a creature reads their forbidden book. They do not age, but can be killed.

Usually evil. Always chaotic.

Babadooks are about the same size as humans, though they tend to be on the tall and thin side. Your size is Medium.

Your base walking speed is 20 feet. You have a flying speed of 30 feet and a climbing speed of 20 feet. 

The Babadook thrives in darkness. You have superior vision in dark and dim conditions. You can see in dim light within 120 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

You always know the location of the creature who awakened you. You also know whether they are alive or dead, and have advantage on attacks against them, and attempts to use your Possess feat on them.

You have resistance to bludgeoning, piercing, and slashing damage from nonmagical weapons. However you are vulnerable to radiant, fire, and psychic damage. 

Once per long rest, you can possess a creature. 

On your turn, as an action, you can attempt to possess a creature. The creature must make a Wisdom or Intelligence save against your Charisma score +1d6.

While possessing a creature, you do not occupy a physical space, cannot take any damage other than psychic damage (any other damage is taken by the host body), and you know the stats and HP of the creature you are possessing, as well as all of its known spells (if applicable). If that creature is bloodied, you are forced into a square adjacent to the creature.

While possessed, the target is under your control. On your turn, you can perform any of the actions the target can. You can also forego your action, bonus, action, and movement, and instead roll 1d6 and add it to your Charisma modifier to create a new save DC. If you do this, you must use the new save DC.

On its turn the target can attempt to save out of its possession, rolling against the established DC, and adding its Wisdom or Intelligence modifier.  

You are always under the effects of spider climb.

You can be detected by the spell detect evil and good. You register as a fiend.

You can speak, read, and write Common and Infernal, as well as the language of the Creature who awakened you.