Lotharganin is a realistic simulation like world in the third season of 12 Oz. Mouse. The land itself is shown to covered in grass making it a grassland with flowers, bodies of water, forming an ocean, large skies, has a stone-hedge, and islands (one particular island with trees is seen in the background.). This is one of the main settings of the season, and appearing in every episode. Some of its inhabitants are Mouse, Aria, Professor Wilx and the Eye (traveling via boat) end up living in a Mysterious Laboratory inside the world. A T.O.P.A.Z. experiment is shown here, but then failed by exploding, leaving all of its leftover remains as parts, which fall on the ground.
Other creatures seen in this world are Bow-tie Bots and Pineapples in a jail, the same jail that Golden Joe and Peanut were trapped in, which rises out of the ocean, and the duo escape via jet skis out of prison, at some point they are sucked into the ocean to the laboratory to find Fitz, Aria and the Eye are trapped behind Wilx's laser case. Olof Mörck and Elize Ryd from The Castellica visit this world in "Portal to the Doorway."