Elmo Shows Abby How to Pretend
S38:E23
2007
IMDb
Abby Cadabby looks for Elmo, and introduces the viewer to her toy frog, Prince. When Elmo sees it, he doesn't understand how a frog could be a Prince, until Abby explains he was a prince that got turned into a frog. She kisses the frog doll, and POOF! it turns into a prince doll (and vice versa).