The wak-wak is a vampiric, bird-like creature in Philippine mythology, and is said to be a witch. It is said to snatch humans at night, similar to the manananggal and the ekek in rural areas. The difference between the mananggal and the wak-wak is that the latter cannot separate its torso from its body while the former can. Some believe it is also a form a vampire takes. Other people contend that a "wak-wak" is a Philippine night bird which functions as a witch's familiar similar to black cats in Western mythology.
The sound of a wakwak is usually associated with the presence of an unglu (vampire) or ungo (ghost or monster). It is also believed that this monster is called "wakwak" because of the sound it makes when it flaps its wings while flying. When one hears the wakwak, it is looking for possible victims. If the sound of the wakwak is loud, it means it is far from you. Otherwise, it is near and worse yet, it is about to attack. It slashes and mutilates its victims and feeds on their hearts.
The wakwak is often described by old folks to have long sharp talons and a pair of wings similar to those of a bat. It uses its talons or claws to slash its victims and to get their heart. Many say that its wings are also sharp as a knife.<ref> (2003) Mga Engkanto: A Bestiary of Filipino Fairies. Philippines: eLf ideas Publication. </ref>
The sound that a tiki, tike or teke (common house gecko) makes usually at night when out of sight was discovered by an American who spent much time in the Philippines to be the source of the sound everyone was saying was a "wakwak".
"A Dictionary of Cebuano Visaya" by John U. Wolff published by Cornell University, South East Asia Program and Linguistic Society of the Philippines 1972 defines wak-wak as:
- noun bird which comes out at night, so called from its call. Its call signifies the presense of a vampire (unglo) or in some beliefs, it is a form the vampire takes himself.
- verb 1 [A13] for the wakwak to be about; 2 [a12] victimize someone with vampiritic activity. paN- verb [A2] go about engaging in vampiritic activity. -un noun = UNGLU, noun
- wakwak2 noun the West piece of Mahjong = WISTL.