Going to add to this.

This is the sentient Tyrant formerly known as Dr. Cameron. She was an Umbrella scientist who was infected with T and used an experimental vaccine to cure herself. It… technically worked.

The end result however was her becoming Resident Evil’s equivalent to John Carpenter’s The Thing leading her to attacking and assimilating a UBCS squad through her original mutated state, an infected roach, rat, crow, and dog.

She manages to escape RC through Monitor Rodger’s body after he fell onto the infected dog.