Guest Stars Jeff Bennett voices Choose Goose Jeremy Shada voices Finn Tom Kenny voices Simon Petrikov Maria Bamford voices Sandy Kevin Michael Richardson voices Sir Soda Kevin Michael Richardson voices Smudge Charlotte Nicdao voices Ancient Glass Princess Charlotte Nicdao voices See-Thru Princess Dee Bradley Baker voices Molto Larvo Erica Luttrell voices Elise Jeff Bennett voices Limeston Audrey Bennett voices Young Marceline Michaela Dietz voices Glassboy Co Starring John DiMaggio voices Additional Voices Tom Kenny voices Additional Voices Hynden Walch voices Additional Voices Pendleton Ward voices Additional Voices Niki Hyun Yang voices Additional Voices Maria Bamford voices Additional Voices Dee Bradley Baker voices Additional Voices Jeff Bennett voices Additional Voices Kevin Michael Richardson voices Additional Voices Charlotte Nicdao voices Additional Voices Olivia Olson voices Additional Voices Erica Luttrell voices Additional Voices