Big Bang Theory Soft Kitty Junior Pajama Set Purr yourself to sleep in this cute and comfortable Big Bang Theory pajama set! The Big Bang Theory Soft Kitty Junior Pajama Set includes a white baby tee tank top with pink ringers, and pink pants with a drawstring waist. The baby tee features a smiling, gray Soft Kitty with the words to the Soft Kitty Song from the TV series The Big Bang Theory , Soft kitty, warm kitty, little ball of fur. Happy kitty, sleepy kitty, purr, purr, purr. The pants have repeated images of Soft Kitty's face and a white atomic symbol.