Death tree

Death trees, also known as "the Moving Trees," were a dangerous type of tree native to the planet Querkus.

Biology
Death trees resembled old normal trees, however, they were able to move and were extremely vicious. A Death tree was strong enough to easily rip apart a Dalekanium casing, they were also almost impervious to Dalek Gunstick fire.

History
The threat of a Querkus attack prevented Querkus from being colonised by humans but centuries later, the unknowing Second Dalek Empire invaded Querkus to establish an new front in the war against humanity. A Dalek scout craft was sent and at first encountered no trouble but within moments they were attacked by the Death trees. This attack enraged the Dalek Supreme, who sent a battle cruiser which wiped out all life on the world with cobalt bombs, leaving Querkus save for Dalek colonisation. (NOTVALID: Roots of Evil)