How COOL is that?
The Big Bang Theory Season 12, Episode 20
♪ The Earth began to COOL
The Big Bang Theory Season 12, Episode 13
♪ The Earth began to COOL
The Big Bang Theory Season 12, Episode 10
♪ The Earth began to COOL
The Big Bang Theory Season 12, Episode 12
No, it's not COOL.
The Big Bang Theory Season 9, Episode 23