Faceworm

Faceworm is a giant serpentine monster with a head that resembles an old man.

In the English release of the manhwa, this monster is known as Face Mask.

Story
At the beginning of the manhwa, Chaos and Iris are seen hunting down Faceworms, which have a bounty of 5,000 Zeny. After cutting down a few normal ones, they eventually face off what appears to be the Faceworm Queen. They succeed in destroying it and collected a fang off each one they killed as proof to receive their bounty reward.

Other Appearances
The Faceworm Queen was planned to be a killable monster in Ragnarok Online, but due to the complexity of its body and the effort required to animate it, it didn't get implemented into the game early on. However the card it would drop was still added anyhow, even though there was absolutely no way for a player to obtain it. Recently, both the Faceworm and the Faceworm Queen were redesigned from their original manhwa versions and implemented into RO.