The "Anniversary Song (Happy Version)" is sung by Happy in the episode "You Ain't Seen Nothin' Yeti!" Happy meets Jollywood's postal carrier who refused to deliver a Jollygram -- a poem written by Grim for Hildy on their anniversary -- to the Glooms. Happy agrees to deliver it for him, and after he set the poem to music, he's a bit disgusted at the gloomy lyrics. He then rewrote the lyrics to reflect a happy mood.