The Chewong people of Malaysia called a collection of many spirits as a Bas. There are various kinds of Bas, some of which under difference circumstances would attack humans.
The Bas usually ate a ruwai, which is translated to soul, life, or vitality They preferred wild pig, and would set traps to catch the pig’s ruwai. In some cases, humans would get caught in the trap and the Bas would eat the human spirit.
The Bas may also encounter a human ruwai when it traveled around during a person’s dreams.
Generally, the vampire spirit did not attack humans or approach human places, avoiding areas where they saw fire, which was a sign of human presence. But, on rare occasions, the Bas were thought to attack humans.
The Bas is considered a psychic vampire.