Is Dean boggart a Banshee?

It appears you are referring to the character Dean from the TV series "Supernatural". However, there is no mention of Dean having a boggart or being a banshee.

* Boggarts are creatures from the Harry Potter universe. They take the form of your deepest fear.

* Banshees are creatures from Irish folklore. They are often depicted as women with long, flowing hair and a wailing cry that foretells death.

While "Supernatural" has its fair share of mythological creatures, there is no evidence that Dean possesses either of these traits.

Perhaps you are thinking of a different character or scene from the show? Could you clarify what you are referring to?