The Ghost of Christmas Past is a character that appears in Return of the Holiday Seasons[1].
Christmas Past is the first of three ghosts sent by Santa Claus to distract Bun-bun. The ghost tries to get Bun-bun to reflect on the mistakes of his past Christmases, but Bun-bun believes his only mistake was failing to check the wiring on his plastic explosives. Bun-bun did not make the same mistake this year, and blows the ghost up.