Mimic octopus
From Tardis Wiki, the free Doctor Who reference
The mimic octopus (Thaumoctopus mimicus) was a species of octopus which could shape its tentacles to disguise itself as other animals and change its colour using chromatophores.
It was believed that the mimic octopus was the only kind of Thaumoctopus. However, there was a species classified by Maddox as Thaumoctopus memeticus. (PROSE: T. memeticus: A Morphology)
