"Ghost of Butterfly Castle" is the second segment of the sixty-fifth episode of Star vs. the Forces of Evil. It premiered on April 7, 2019 alongside "Princess Quasar Catepillar and the Magic Bell", and is the second segment of the ninth episode in the fourth season.
Moon and River's home in the woods has grown into a small community, but the inhabitants constantly turn to Moon to solve their issues. Unable to keep up with everything, Moon goes to get her old ledger at Butterfly Castle, which is said to be haunted. Upon retrieving her ledger, Moon finds that what has been haunting the castle all along was actually Mina Loveberry. Mina reveals she has been trying to dethrone Eclipsa and was the one who put Yada Yada Berries in her food. Moon tries to convince her that she does not have to fight monsters anymore, but in Mina's eyes she will always be a soldier and Moon will always be a queen. Afterward, wanting to prove her wrong, Moon decides not to solve all her people's problems anymore and lets Mina be as she goes after Eclipsa.
- June 7, 2019 (Southeast Asia)