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 she leaves while Jerry attempts to get to his mouse hole but Mechano senses Jerry and hits Jerry with its tennis-ball-hitter and hits Jerry out the window. Jerry then attempts to use a hose to get to his hole but Mechano senses Jerry still and chops the hose with its axe and knocks Jerry out of the house. Jerry then attempts to use a sling-shot to get to his hole but Mechano senses Jerry again and uses its baseball glove and shoots Jerry out of the house. 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. Its weapons were wreaking havoc in the house and Mammy attempts to get Mechano to stop but since Mechano only responds to the remote, nothing happens. Mechano ends up destroying itself in the carnage. When this happens, Tom returns after hearing Two-Shoes calling him and ends up swallowing the AI unit of Mechano. Jerry managed to obtain the remote and tried to use it, causing Tom to behave like Mechano instead.
- 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 had a name in the actual Cartoon.
- Mechano reappears in the Chuck Jones short, Advance and Be Mechanized.