The Yawn was a snaked-based B.O.W. that lurked around in the Spencer Mansion. It was nicknamed "Yawn" by the Arklay Laboratory team in reference to the way its mouth opens before attacking, which resembled a yawn. It was one of the many test subjects bred specifically as experimental B.O.W.s. The specimen escaped however, and managed to avoid recapture by the scientists in the Arklay Laboratory. It was eventually infected with the T-Virus following the leak in May 1998, and it promptly made the mansion its home, preying on any humans that happened to come across it.

Tier: At least 9-A

Classification: T-Virus infected snake, experimental B.O.W.

Powers and Abilities: Superhuman physical characteristics, natural weaponry (Sharp Fangs), large size (Type 0, 12 meters in length), venomous bite

Attack Potency: At least Small Building level (By virtue of size alone, can swallow a person whole and crush them instantly by constriction, stronger than other B.O.W.s such as the Hunter)

Speed: Average Human while slithering, Superhuman in short bursts (Can keep up with S.T.A.R.S members)

Lifting Strength: Class 25 by virtue of sheer size (weighs 12,000 kg)

Striking Strength: At least Small Building level

Durability: At least Small Building level (It has to be shot by a shotgun dozens of times to be put down)

Stamina: High

Range: Extended Melee Range

Standard Equipment: None

Intelligence: Animalistic

Weakness: None notable

Notable Attacks and Techniques:

•Bite: Yawn uses its enormous fangs to attack, injecting venom and leaving deep wounds. Due to its mutations and enormous size, the venom injected is enough to knock a fully grown person unconscious and kill in the span of 5 minutes.

•Constriction: Yawn surrounds its prey and crushes them near-instantly with its large fangs.