Ah yes, "Mole World", whose main inhabitants look nothing at all like moles, but do seem to resemble WORMS in both form and function. What, "Wormworld" too hard to say Kara?
You begin to see why the writers of this era named a shapeshifter "Chameleon Boy" when his powers have bugger all to do with Chameleons or any variety of blending in (which at least works as an excuse for the TARDIS Chameleon circuit, which WAS supposed to make sure the TARDIS blended into it's surroundings)