Kat later uses a boulder to assault a mentally impaired Coop in Me Coop, You Kat and while it hits, his neanderthal DNA makes him too hard-headed to seriously injure with it, only making him angry.
This is seen in the "Me-Oh Me-Oh Meow" episode; Kat, tired of his new collar, manages to get it off and then modifies it so it can torture Coop. Kat had become tired of his new collar telling him what to do all the time, so he did all he could to get it off; once he did, he figured it was the perfect opportunity to torture Coop with it. The collar is nothing more than a modified pet collar, the only difference is it now has a human. function in addition to dogs and cats.
This is Kat's second invention; it is seen in the episode "Do Not Fort Sake Me" when Kat tries to communicate with his home planet. The device is made out of ordinary household items such as a cookie tray and metal tongs.
In Dial "B" For BabysitterKat modifies Old Lady Munson's garden gnome with some mechanical parts in order to send it to space. Kat's plan ends with success and we can see it floating in space with kind of beacon function enabled. It is possible that Kat tried to communicate with other Kat's or it contained retrievable reports from Earth.
A machine created by Kat in "Storm Drained" used by him to tamper with the weather.
Portal opening machine
In "Beware The Were-Coop" Kat creates a machine that with using energy gathered from the moon opens a portal that transports everything to his home planet. Even if the machine exploded later, It was successfully utilized to send Fishy Frisky Bits back to his planet.
Modified leaf blower
In "Catboy Update" Kat modified leaf blower, making it powerful enough to send Coop flying in the air.
In "Fumblebee" Kat installs some upgrades on the lawnmower, including big laser turret.
As seen in the episode "Nip/Duck", Kat built this to resharpen his claws after the Vet trimmed them down; this device is also made from everyday household items such as a blender, cheese grater and an orange juicer.
As seen in the episode "Search and De-Toy", Kat built this rocket in an attempt to send food back to his home planet; the rocket is made out of ordinary household products such as a blender and a food funnel.
This is also seen in the episode "Search and De-Toy"; seeking revenge upon the RC Helicopter, Kat modifies a TV remote and turns it into a remote control for the RC Helicopter. Kat thought that Coop interfered with the rocket on purpose so he decided to take control of the RC Helicopter and crash it into Mrs. Munson's yard. This device is a modified TV remote; it is now able to pick up the RC Helicopter's frequency and wavelength.
This is one of Kat's more advanced inventions; it is seen in the episode "Flu_The_Coop", to put Coop to sleep and keep him from covering Kat in his germs. The contents of the formula might be comprised of soothing ingredients or it could just be made of a very powerful sleeping agent found on Earth or Planet Catnip, the exact ingredients are never revealed.
In the episode the Allergy, Kat invented this to make Burt thinks he's allergic to Coop, made with hot sauce, powder pica, poison ivy, bottled pepper and onion.
In the episode "Just Me And GlueKat changed the warrior Lord Megazurg to attack Coop. This backfires when it also targets Kat, so Coop and Mr. Kat work together to destroy it.
Modified pencil sharpener
In "How the Test Was Won", Kat fixes Coop's pencil sharpener to make it attack him by eating all the pencils and then spitting out all the erasers and metal parts.
In "One Big, Happy Family", Kat creates a machine resembling a blender to mess up Coop's body, or "scramble his face". Coop soon figures out who made it, and detonated it. Somehow, when they get home, Kat manages to get it back. No one knows how he got it back, especially with Millie next to him 24/7!
The most possibly deadly weapon, and almost eaten by Millie. In "One Big, Happy Family", Kat makes Millie cupcakes poisonous. This was probably a trap for Burt or a way to torture Coop since Burt told him to sit in the corner on an old bar stool and not move.
In "Play N'Ice" Kat has a secret cell where he hides all his cat food. The lock to his food cell is voice-activated. It was seemingly destroyed when it and the ice castle collapsed on themselves. However it did not collapse completely, destroyed ice castle remained on the surface, meaning that ground didn't break and contents of storage remained buried under ice.
Seen in "Planter's Warp" and The Grass is Always Meaner, respectively. The liquid can turn plants into monsters. Ingredients include ketchup, marshmallows, and Kat's hairballs. It also smells horrible to some humans. It makes grass grow over 7 feet tall.
In U.F. FloatKat has an idea to make the families U.F.O. float fly, so he can return home. So he makes proper fuel to go with it.
Also in U.F. FloatKat turns a parade float into a different-looking spaceship to try and get home.
Kat had made another rocket in Kid vs Kat vs Christmas, which was designed like Coop's Captain Blasteroid rocket but got electrified accidentally by Coop when he was connecting the wires for the Christmas lights.
In It's a Rocket, Man, Kat made a telescope out of a glass cup, magnifying glass and Millie's glasses in order to see how the delivery pod with his weapons of doom were doing.
Kat keeps it in his inventory and uses it more than once. It fires homing missiles.
Rocking chair factory rockets
After destroying the interior of the rocking chair factory in "Keep On Rockin'" Kat attempts to send the whole building into the sun using powerful engines. It ends with a factory landing somewhere in the park.
In "Rebel with a Claw" Mr. Kitten uses explosives that Kat stored in his scratching post lair to threaten Burtonburgers. Kat defused them in end and probably keep them after. However, these could have been built on his planet, and Kat successfully received them somehow.
With this invention, Kat is able to make everything invisible, as we see in "You Kat See Me".
Made by Kat in "Down the Drain", it simply creates a hole in every object on the path of the laser, it has an extremely long-range, laser shot went out of from Burtonburger's House and kept its trajectory through space.
in "Flea Brains" Kat designs numerous brain controlling flea like nanobots to suppress and enslave the consciousness of an individual by burrowing through the earlobe straight to the mind. Afterwards, the cat can make him or her do anything he wishes them to via his new remote, a sonic blast however is shown to short out the bug thus dissolving the will bending effects.
It is seen in the short Katnapped and in Russian version catnapped episode is called in the dreams the kat.
It is a special powder made by Mr. Kat for him. It is used by Coop to enter the dreams of Mr. Kat and ruin.
Cybernetic mind control
It is seen in It's All In Your Head. This invention is made by Kat. It has used to get a USB key with a super-secret data, to destroy anti-alien laser satellites. He performed it with Coop's unintentional help.
Seen in Good Luck Harm. Kat has a blueprint of the suit, then Coop steals it in the middle of a hockey game but then Kat gets it back and puts all the good luck charms in the neighbourhood and puts it in the middle.