Scribble creature

When Chloe Webber swallowed an Isolus she drew a Scribble.

History
Due to the abilities the Isolus gave her, the Scribble became a living scribble of graphite, animated with ionic energy. It hid inside a garage and when Rose Tyler opened it, it leapt out at her. The Doctor shone his sonic screwdriver on the creature causing it to die and retract into a small ball. While examining it in the TARDIS, the Doctor discovered it was made from graphite, which he demonstrated to Rose by erasing part of it with a pencil eraser. The Doctor and Rose then knew that drawings were mysteriously coming to life. (DW: Fear Her)