Butterfly
From Tardis Wiki, the free Doctor Who reference
Butterflies were Earth lepidopterids K9 once encountered on an unnamed planet in another dimension, partially inhabited by ex-Tellac miners. They lived alongside other Earth animals from widely varying periods of evolutionary history. Unlike most species of butterfly on modern Earth, however, these had a wingspan of about ten feet, as many extinct species did on Earth in the prehistoric past. (AK9: K9 and the Missing Planet)
