Hippopotaduck posankka
I recently purchased this purple hippo from the post office. (I also got a cute book of kitty stamps while I was there.) It doesn't look much like a hippo, but I couldn't figure out what else it looked like until Kelly worked out that it is also a duck. Hence hippopotaduck.
This reminded me of a crazy thing in Turku, Finland called the posankka. The word posankka is a combination of the Finnish words for pig and duck. It has been seen in various locations around Turku, including on the river Aura.
My friend Dag has a page about the posankka giving a vague explanation for its existence.
See also xmas posankka.