The Shadow Blot, also known as the Phantom Blot, the Storm Blot or simply the Blot, is a fictional sapient creature seen in the Epic Mickey series.
The Shadow Blot was accidentally created by Mickey Mouse using magic paint and thinner belonging to the enchanter Yen Sid. The Blot is a gigantic monster resembling a large muscular demon, made of a bubbling mix of black ink and lime-green thinner. Accidentally banished by Mickey into Wasteland, a pocket dimension inhabited by the peaceful King Oswald and his subjects, the Blot rained destruction upon it (in what is known as the Thinner Disaster), using his ability to drain lifeforce from other paint creatures like toons. Oswald was able to seal the Blot into a giant jug, but only at the cost of the life of his beloved wife Ortensia.
Moreover, the Blot was not truly gone, as it still mustered enough strength to send minions created from drops of his own body, the Blotlings, into the Wasteland. The largest Blotling, called the Blot's Shadow, who acted as the blot's second-in-command, decided to escape into the real world. To do so, he needed the heart of Mickey Mouse, whom he dragged into the Wasteland for this purpose. Although Mickey managed to defeat the Shadow, it kicked off a reaction chain of events that freed the real Shadow Blot from his prison. The creature started to drain Wasteland of its paint, and threatened Mickey's friends Oswald and Gus's lives if he didn't give him his heart. Nobly, Mickey sacrificed himself. However, with the help of the freed Oswald and Gus, he eventually managed to destroy the Blot for good.