Changes

The Leviathans have sharp teeth within an expanding jaw, and possess a bifurcated tongue. They feed on human internal organs - sometimes with cheese. All Leviathans absorbed everything that Castiel knewThey are at least occasionally cannibalistic, as he was eating others of their original vesselown kind.<ref>[[7.06 Slash Fiction]]</ref> Leviathans are thus capable of killing one another.

They can take mimic a particular human form following contact, or if they obtain some DNA from a person. They are then aware of all that person's thoughts and feelings, and even hallucinations.<ref name="seven06">[[7.06 Slash Fiction]]</ref> All Leviathans absorbed everything that Castiel knew, as he was their original vessel. When wounded they "bleed" black goo.