My Friends Tigger & Pooh - Season 2 Episode 29 -

Darby's Pony: Seeing that Darby is always reading a book about a girl and her pony, Pooh and Tigger get the idea that Darby really wants a pony. They make it a Super Sleuth case of their very own and try to figure out how to get her one. They decide to enlist Eeyore's help, making him into a pony for Darby.