Thinner is a substance in Epic Mickey that can be wielded by Mickey Mouse when he uses the Paintbrush. Thinner destroys enemies and is able to melt cartoon characters. It can also thin the Beetleworx armors, but cannot destroy them. Thinner is the functional counterpart to Paint.
Thinner is green paint thinner that can be used as a solvent to dissolve and destroy foes, buildings and obstacles in Wasteland, whether they're good or bad. It can be used on cartoon characters, causing them to melt and get absorbed in the ground unless Mickey uses paint on those characters again. Thinner is the one of the tools Mickey can use on his quest to become an epic hero. Thematically, Thinner represents Mickey's "mischievous" side, due to the consequences his actions have on the beings he interacts with. In fact, using more Thinner will cause Mickey to drip like the Shadow Blot. The inhabitants of the Wasteland, including Oswald, will become negative and fear Mickey the more Thinner he uses.
By using Thinner more often than Paint, Mickey will be able to attract Turps. Thinner also replaces water in Wasteland and will hurt Mickey if he touches it. This Thinner replacing the water are called Thinner Seas or Pools of Thinner. At the end of the game, Thinner Pools turn back into clean-fresh water/Paint.
Paint and Thinner were the elements used by Yen Sid with the paintbrush when he was developing the early phases of the Wasteland. However, when Mickey uses paint and accidentally creates an ink monster, Mickey splashes it with Thinner to get rid of it. With the mix of both Thinner and Paint came the Shadow Blot who escaped into the Wasteland due to the Thinner bottle Mickey accidentally spilled onto the world model. As a result, the Thinner washed over the Wasteland, turning it into a dilapidated being of its former self, and allowed the Shadow Blot to defeat Oswald the Lucky Rabbit and took over Wasteland. This event was known as the "Thinner Disaster."
In game, Mickey can use the Thinner along with Paint with the use of his paintbrush. Depending on the amount of Thinner used, Mickey will earn achievements that highlight his more negative actions.
- Thinner is strikingly similar to the Dip, the chemical Judge Doom used to melt toons in Who Framed Roger Rabbit. Not only are their functions similar, but the ingredients used to produce Dip - turpentine, benzene and acetone - are, in fact, used as paint and ink thinners.
- When Mickey uses too much Thinner, the music will sound either sadder or more menacing.
- It seems that the Thinner has a malignant effect on Mickey the more he uses it - using it causes the ink on Mickey to float off him, suggesting a physical transitioning to the Blot itself. Also, in Epic Mickey 2, Mickey seems sadder when he uses Thinner.