Shapeshifter

A shapeshifter was a being imbued with the ability to alter its physical form. (COMIC: The Shape Shifter)

Frobisher, the Whifferdill companion of the Sixth and Seventh Doctors, frequently used his species' shapeshifting abilities on their travels. (COMIC: A Cold Day in Hell!, Frobisher's Story, Changes) Frobisher fell ill with mono-morphia, which took away his ability to shift, leaving him stuck in the form of a penguin. (COMIC: Genesis!) He recovered enough to shift into various forms while battling another shapeshifter, a Kymbra Chimera, aboard the Doctor's TARDIS. (COMIC: Changes)

After leaving the Doctor, they met again when the Time Lord was in his eighth incarnation. However, as Frobisher had taken a humanoid form and was known as Bish, and the Doctor had regenerated, neither recognised the other. (COMIC: Where Nobody Knows Your Name)

Nostrovites were shapeshifting carnivores. A number used this ability to infilitrate the wedding of Gwen Cooper and Rhys Williams in order to extract the unborn Nostrovite from Gwen's womb. (TV: Something Borrowed)