Cats often appear as a theme on It's Always Sunny in Philadelphia.
Father O'Grady mentioned brown cats twice. ("The Gang Exploits A Miracle")
Cats live outside of Charlie's apartment due to the cat food left in the apartment, which as Charlie describes, is to attract cats who kill the rats. The cats meow quite a bit, understandably, so Charlie and Frank have to drink beer, huff glue and eat cat food to induce a feeling of sickness and tiredness. (Dennis Reynolds: An Erotic Life)
Charlie had so much trouble with cat noise that he invented kitten mittens. (Paddy's Pub: Home of the Original Kitten Mittens)
Dee bought a cat but it accidentally got trapped in her wall. (Mac and Dennis Break Up)
Maureen Ponderosa self-identifies as a cat. (McPoyle vs. Ponderosa: The Trial of the Century)