Scratchman

Scratchman, known informally as Scratch and understood as the Devil by the Fourth Doctor, was a pan-dimensional form of energy who fed off the emotional vulnerabilities of others, giving them a little power in return. He appeared as a man in a suit with a globe of white fire for a head. (PROSE: Scratchman) He also used the name Harry Scratch. (PROSE: Doctor Who Meets Scratchman)

Biography
Scratchman travelled from universe to universe, draining them of their energy and turning their inhabitants into grotesque creatures called Sallows. He ruled his alternate dimension for millions of years until it too ran out of resources for him. Thus, he struck a deal with a Cyber-Leader in the form of a virus that converted people into living scarecrows. This allowed Scratch to create a small rip between his universe and the Doctor's universe in an attempt to conquer it next.

The Fourth Doctor, Sarah Jane Smith and Harry Sullivan arrived on an island in Scotland where the scarecrow virus began to infect its villagers. After failing to prevent the islanders and his companions from being infected, the Doctor piloted his TARDIS to Scratchman's realm. After making it through his designated Hell, the Doctor met Scratchman, who offered him to become the ruler of his native universe in exchange for Scratch being able to feed off its souls' energy. The Doctor declined, plunging him and his revived companions into a massive game controlled by Scratch. (PROSE: Doctor Who Meets Scratchman, Scratchman)

Harry was able to trick the Sallows into no longer powering Scratchman's castle, so Scratchman created a scarecrow army of monsters from the Doctor's past. However, the Doctor showed Scratchman his own fear and caused him to become afraid himself, his universe imploding on him. The Doctor was placed on trial on Gallifrey for these events, and what his own fear was that he used against Scratchman he refused to divulge. (PROSE: Scratchman)

According to another account, the Doctor simply by beat Scratch's giant game of pinball, causing him to explode into a million pieces. Out of his suit came a lead-coloured ball, which the Doctor played cricket with. The ball shattered, but one fragment contained a lizard with Scratch's head. (PROSE: Doctor Who Meets Scratchman)

Behind the scenes

 * In the unproduced film Doctor Who Meets Scratchman, Scratchman was intended to be played by Vincent Price.