The opposite of logic, usually used in hilarious context. Most often understood if you are a nerd/geek ;).
Nerd: If 1+0=1, and you multiply both sides by 18 to get 1 + 0 x 18=1 x 18. And according to universal rule of PEMDAS, this gives us 1+0=18. Thus, any number is divisible by any other positive rational integer, and thus there is no such thing as a prime number.
Geek: Dude, that's connalogic.