The Mech, as the name suggests, is done in Prescott's likeness, with the head resembling his own coming from a large castle and with two arms protruding from either side.
In Epic Mickey 2
In order to take the paint path, Mickey must use Invisible Ink to take the Band Concert V2 projector on the balcony of the White Rabbit's house in the Alice Area of the Floatyard. Taking the Old Mill V3 projector in that area will skip ahead to the second half of the Thinner version of the battle.
For the first part, Mickey has to fill the pump on the cannon within the Mech with either paint or thinner (similar to the fight with Petetronic in the first game) while dodging flaming cannonballs and thinner bombs. When the pump is full, Oswald is able to use his remote to reprogram the cannon. This has to be done a total of three times and the cannon is protected by electrified panels and all the panels surrounding the cannon can be thinned out. Once the cannon has been defeated, Mickey and Oswald will leave the Mech for the second part.
In this path, the Mech will be friendly to you and Prescott will angrily get his Mech to get his fighting face on. You can then use the boulders the Mech launches to break the six plates on the floor by putting Mickey and Oswald on top of them. It will take three hits per plate to break them to reveal gears that Mickey needs to paint in and panels that Oswald needs to power up. When all of these are painted in and zapped, the cranes will close the doors that the Mech came from thus trapping it, ejecting Prescott out, and giving you the paint ending for it. A tip for when you are inside the Mech, try to use a Television Sketch to distract the Tank, giving you a good chance to fill it with Paint or Thinner. Another good tip is to thin the reloading pipes, causing the cannon to lose the ability to fire Thinnner Bombs.
In the Paint Ending, the Mech will be happily waving at everyone gathered to see the parade.
In this path, the Mech will be damaged and Prescott will fix his Mech to destroy Mickey and Oswald. If you used the secret projector in the Floatyard, Prescott will introduce his Mech as his greatest creation prompting Mickey to "need a bigger brush". You can then use thinner to thin out the armor of the Mech. Then, you can do a spin attack to launch back one of the Mech's cannonballs. Repeat this twice more and the Mech will be destroyed, thus ejecting Prescott from the machine. In the Thinnner Ending, the Mech will be broken and will damage a building in Mean Street.
- In the reveal trailer for the 2nd game, the mech battle is spoiled near the end, but most of the mech's face is thinned out to prevent obvious spoilers.