The Mojo Vac was a huge mech for Cortex. It never actually appeared in any game but the player can see it in Episode 4's concept art in Crash of the Titans. It is next to a drawing of a Yuktopus. It has a single red eye and it was most likely to be the boss in the Temple of Zoom, but the Yuktopus replaced it. His head has great similarity with the head of Cortex, except it has one red eye and has written "Mojo Vac" on the forehead, his right arm is a giant gear, while the left is a mojo vacuum, and the torso is a tank filled with Mojo.
In another piece of Episode 4's concept art, the Mojo Vac would've had a totally alternative design resembling a kind of mechanical elephant with a vacuum like trunk, with a full tank of mojo on the back with "Mojo Vac" written and two large tusks that could out for use as decks.