Not to be confused with Robocat.
Mechano first appears when Tom is sleeping on his bed. Mammy Two Shoes, Tom's owner, smugly tells Tom after getting a package in the mail that Mechano, a mechanical cat that has a cannon, axe, hammer, tennis ball-hitter, and a mouth that holds a baseball glove, is taking Tom's job as a mouse catcher. Tom sadly leaves while Mammy Two Shoes smugly tells him "Maybe you can find an old fashion house that needs an old fashion cat!" She orders Mechano to "Keep that mouse (Jerry) out of the house" and leaves while Jerry attempts to get to his mouse hole, but is unaware of Mechano, who senses him and hits him with his tennis-ball-hitter and hits Jerry out the window. Jerry then attempts to use a hose to get to his hole, but is no match for Mechano, who senses him still and chops the hose with his axe and knocks him out of the house. Jerry then attempts to use a sling-shot to get to his hole, but fails when Mechano senses Jerry again and uses his baseball glove and shoots Jerry out of the house with a cannon (using Jerry's tail as the fuse, hence his scorched tail in the next scene). Jerry then uses multiple mechanical rats to distract Mechano, who is attempting to attack all of them, but is unable to take them down effectively. His weapons are wreaking havoc in the house and allowing Mammy to attempt to get Mechano to stop, but since Mechano only responds to the remote, nothing happens. Mechano ends up destroying himself in the carnage by wrecking off his head, breaking his body apart, and breaking his legs. When this happens, Tom returns after hearing Two-Shoes calling him and ends up swallowing the AI unit of Mechano. Jerry manages to obtain the remote, and tries to use it, but succeeds by causing Tom to behave like Mechano instead and chase the mice all around the house.
- Mechano has two weaknesses: he only responds to the remote, and is designed for single-target only. Therefore, there is no failsafe if his automatic systems go haywire, such as when he is attempting to attack multiple targets simultaneously.
- Mechano does appear in the game Tom and Jerry in House Trap as an enemy for Jerry to beat. Although he isn't playable in the game, he is invincible and doesn't need to carry weapons unlike Tom since he can shoot a bowling ball if Jerry is too far and is able to attack Jerry with his mouth in a combo of 3 or 2. There are still mechanical rats around the house that can be used to distract the machine for player to attack but each mechanical rat only runs around for 8 seconds.
- Mechano is called Mechani-cat despite the fact that he already has had a name in the actual Cartoon.
- Mechano reappears in the Chuck Jones short, Advance and Be Mechanized.