The Sapling

 was one of the saplings generated by the Planting.

The Scream, wanting to be remembered, used Eleventh Doctor's and Alice Obiefune's memories to form a "new creation". He intended to take over the Sapling, to be able to cover entire planets. This way, no one would be able to turn his back on him, which meant he would always be remembered.

However, Alice materialised the TARDIS around the Scream and his machine, stoping the process in the middle. The Sapling became a individual, sentiend being, containing both the Doctor's and Alice's memories. Because he had the memories of a Time Lord, he was aware of being predisposed to genocide. He asked to Doctor to destroy him, claiming this would be the safest thing to do. (COMIC: The Scream)