Kymbra Chimera

Kymbra Chimeras were a shapeshifting species similar in abilities to the Whifferdill.

Biology
The Doctor described them as a primitive relative of the Whifferdill. They powered their shape changes with stolen energy. They were unable to accurately copy clothing, so it appeared fused to the flesh. (DWM: Changes)

History
A Kymbra Chimera was brought onboard his TARDIS by the Doctor when it was disguised as a cute Swuffle. The Doctor placed it in a synthetic habitat in the TARDIS Zoo. When it escaped, it took on the appearance of the Doctor and then Peri. It battled with the Whifferdill Frobisher, each changing to overpower the other. The chimera was winning when it was sucked out the TARDIS by the Doctor. (DWM: Changes)