(Flashback to little Sam and Dean…)

Sam Winchester: Are monsters real?

Dean Winchester: What? You’re crazy.

Sam Winchester: Tell me.

Dean Winchester: I swear, if you ever tell dad I told you any of this, I will end you.

Sam Winchester: Promise.

Dean Winchester: First thing you have to know is we have the coolest dad in the world. He’s a superhero.

Sam Winchester: He is?

Dean Winchester: Yeah. Monsters are real. Dad fights them. He’s fighting them right now.

Sam Winchester: But dad said the monsters under my bed weren’t real.

Dean Winchester: That’s because he’d already checked under there.

From Supernatural – Season 3 Episode 8: ‘A Very Supernatural Christmas’ (3×08) | Produced by The CW