Barney: Marshall, what you're suggesting is an elaborate, long-term lie that requires tremendous commitment. A nice guy like you can't pull that off.
Marshall: Sure I can.
Barney: Lie to me right now.
Marshall: Okay. I have a spaceship.
Barney: What kind of fuel powers your spaceship?
Marshall: Okay, I don't have a spaceship.
Barney: No! Stand your ground! If someone questions you, distract them from the original lie with more lies. Here, let me demonstrate. I own a pony. Ask me a question.
Marshall: [scoffs] Okay. Um, what color is your pony
Barney: Well, when I first got Dandelion, she was a deep, chestnut brown, but, sadly, her stable is located near a chemical plant, which contaminated the drinking water. So over time, she's turned a sickly, grayish-white color and there's nothing that the vet can do to fix her.
Marshall: My God! That's horrible. Is Dandelion going to be okay? [Barney smiles] Okay. All right. You are good! Dandelion's not even sick, is she?