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1.
A very interesting cat that lives in Toronto. Usually can be found pulling ninja like moves while fucking mad cat hoes.
Rob: Damn i'm proud to own this balling cat named Serious.

Ben: Your cat is gay.

Serious Cat: Get at me "breaks Ben's neck"

Rob: LOLOLOLOLOL
by skeezernator April 14, 2011
 
2.
A very fucking serious white cat popularized by imdb.com user Timmys_DownTheBloodyWell. He is Emperor and Supreme overlord of a board called "The Sandbox" as well as President of the Anti-squirrel coalition. In his spare time he enjoys spreading awareness of the seriousness of a thread, killing infidels (mostly squirrels), and he also taking long llama rides on the beach.
*A poster tries to joke in a very serious thread*
Serious Cat: *stares with a look of extreme superiority and seriousness*
by TDTBW September 16, 2007