Sentient nebula
From Tardis Wiki, the free Doctor Who reference
The sentient nebulae of Blecplam Two and a Half was observed by the Thirteenth Doctor, Yasmin Khan, Graham O'Brien and Ryan Sinclair in 3912.
There they encountered Leon Perkins's hand sticking out of a portal.
The Doctor previously saw them in an earlier incarnation. (COMIC: A New Beginning)
