Puddle

The sentient oil took the form of a puddle. (TV: The Pilot)

The Abzorbaloff melted into a puddle. (TV: Love & Monsters)

Following the Abzorbaloff's death, the Tenth Doctor came to believe that he had "unpuddled" himself, only to learn that what appeared to be the Abzorbaloff was actually his father. (WC: The Genuine Article)