It is believed to issue forth from its lair during Holy Week, looking for children that it will kill for their hearts, which it fashions into amulets. According to the legend, there are families known as Sigbinan ("those who own Sigbin") whose members possess the power to command these creatures, and are said to keep the Sigbin in jars made of clay. The Aswang are said to keep them as pets, along with another mythical creature, a bird known as the Wak Wak , Wek Wek..