The Batibat or Bangungot is a revengeful demon found in Ilocano folklore that causes the fatal nocturnal disease known as “bangungot” (nightmares).
Usually, a batibat takes the form of a huge, old, fat woman that resides in trees. She come in contact with humans when the tree where she resides is cut down and used as a support post for a house. If this happens, the batibat will migrate into the holes found in the post.
The batibat does not want humans to sleep near its post. When a person does sleep near it, the batibat transforms to its original form and attacks that person. It sits on the chest of its victim until he suffocates.
To ward off the batibat, one should bite one's thumb or wiggle one's toes. In this way, the person will awaken from the nightmare induced by the batibat.