The magical city of Phogghom had a highly advanced waste disposal system, in which everything was dumped into the nearby lake. One year, there was a severe drought, and the level of the lake lowered to reveal Wetfight the Mouldering and the Fungi from Phogghom!! The magical waste from the city had formed these new life-forms: Wetfight the Mouldering himself, a giant pile of household wastes and mud, and the the Fungi, who had been mutated from regular mushrooms. Wetfight has enslaved the Fungi and ordered them to bring him more waste, so that he can grow large enough to envelop the city of Phogghom. Meanwhile, the citizens are enjoying their new garbage-collecting service.

This picture was drawn in pencil, and coloured in photoshop for the Seventh Sanctum Evil and Co. contest.

EDIT:
A link to the Seventh Sanctum site can be found here