Party of One, the twenty fifth episode of Season One was originally aired on April 29, 2011.

In this episode, Pinkie Pie investigates her friends’ excuses for not attending one of her parties.

It also features a song, Pinkie Pie's Singing Telegram, in which Pinkie Pie sings it to Twilight Sparkle, Rarity, Applejack, Rainbow Dash, and Fluttershy as a way of inviting them to her pet alligator Gummy's first birthday party.