Murdercat
The 3rd cat in any household, completing a kitty cabal, ultimately leading to the death of everyone in your household. A little known ancient designation originating in Egypt in the 1st Kingdom, and was the undoing of more than one Royal Family. The main reason British Royalty has always preferred canine companionship. Rumored to be the most likely cause of death in the case of Cleopatra. However, this was suppressed for centuries by the Meowmiati, a clandestine organization made up of elderly cat ladies, who changed the narrative to blame a serpent, further vilifying the snake.
After all other suspects had been cleared, detectives determined the family unknowingly brought about their own demise by bringing a third feline, a Murdercat, into their home.
Murdercat
The German Leopard 2 main battle tank
The Russians were ambushed by a pair of Ukrainian Murdercats. They TikToked the whole thing. It's awesome.