Bull

The story told by Yu-Han Sung is that the Bull is a fearsome unidentified creature that made its appearance in the Wine Glass a few years ago. It has an enormous appetite. And is a creature that typically wouldn't exist at such a low level of the Tower which makes its presence there strange. It is incredibly strong and has amazing speed, and because of this it is at the top of the food chain in the wine glass. Because of its temper and appetite it has gained the nickname "Bull". It eats both Mangdol Whales and humans. Several Regulars have fallen prey to it already. Sunwoo Nare notes that an strong enough Anima would be able to control it.

It later revealed that a powerful Anima, Ren, uses the Bull in order to eliminate Anak during the Submerged Fish Test. However, when this failed, it was sent to kill Baam. After being frozen several times by Baam, it was blasted through the mouth and fell to the bottom of the Wine Glass, where it presumably died.

Yu Han Sung noted that if you look closely its silhouette resembles Rak.

It also helps give an idea of how strong Baam has become, as Yu Han Sung stated it should only be in much higher-leveled floors, and Baam single-handedly killed one. Although, it's also possible that being in the Wine glass managed to boost Baam's shinsoo levels for the time being, hence allowing him to dispatch of the Bull which would've been impossible given his levels.