At Crowley's Lair, as Lucifer prepared to kill Crowley with an angel blade, a rat approached him. Seeing this and while Lucifer was distracted smirking at the other demons, Crowley left his vessel and possessed the rat instead. As a result, when Lucifer stabbed Crowley, he only stabbed an empty vessel and wrongly believed he killed Crowley.
Following the departure of Lucifer, his demons dragged Crowley's empty vessel away, followed by Crowley in the rat. After the demons had buried his empty vessel and left, Crowley left the rat and returned to his usual vessel.Crowley later told the Winchesters that while possessing the rat he had a long time to think and during this period, realized that he hates his job as King of Hell.
- This is the first known rodent to become a vessel.