Catroots was a Nintendo 64 game of unknown genre developed by Marigul Management. Catroots is a rather mysterious title as it was never officially announced despite a tech demo being shown at E3 2000. There are very little details known about the game.
Eventually, Shigeru Miyamoto himself was interviewed. He confirmed that the game was being developed by Marigul and that an official announcement on the game was yet to be made. As Catroots was in development late into the Nintendo 64's lifespan, it may have been canceled due to the release of the Nintendo GameCube in 2001.
"We were told to put it out there."
The teaser showed cats and mice feuding in a similar style to Tom & Jerry or The Simpsons' Itchy & Scratchy. An unknown portion of the teaser was uploaded by IGN, which shows a red cat getting chased and attacked by a mouse, using weapons like shurikens, a hammer, and a flamethrower. There are also a few other pictures depicting some different scenarios.
As of the writing of this article, the tech demo for Catroots has yet to surface. Despite the release of the Nintendo GameCube, Catroots was never reworked or ported onto the Nintendo GameCube or any subsequent Nintendo system.