Firebird (species)
From Tardis Wiki, the free Doctor Who reference
Firebirds were bird-like creatures made entirely of fire. They only lived for minutes and were smaller than a hummingbird, but they burned with a rainbow of colours and were incredibly bright. Jack Harkness once saw a firebird and claimed to Gwen Cooper that it was the most beautiful thing he had ever seen. (TW: Immortal Sins)