Nicky

Nicki is a zanna that takes on the form of a mermaid. He was the imaginary friend to a young girl by the name of Zoe in Menomonie, Wisconsin.

Season 11
A young girl named Zoe is having swimming with Nicki until Nicki remembered Zoe to going to the gymnastics. When the little girl passing, she swimming alone in the pool. However, Reese appear and multiplically stabbed her with the Zanna-killing Knife, leaving her bled out and dead in Zoe's pool. After Sully found her dead, he later managed to properly buried her in a ditch, with Sam and Dean assistance.

Appearance

 * Season 11
 * Just My Imagination