Lunch in a Box blog has a post about making your very own pig-shaped boiled egg, using a nifty Japanese (what else?) contraption improvised into an egg mold:
I figured they’d work just fine as ice cream sandwich molds, cookie cutters, and onigiri molds, but I was most curious about how they’d do as hard-boiled egg shapers. You may have seen these crazy gadgets before (photo below): you hard-boil an egg, peel it while it’s hot, pop it into a plastic mold while it’s still hot and pliant, and click the lid shut. Dump the whole thing into cold water for 10 minutes, and you’ve got an egg that looks like a rabbit head or a star.
Link - Thanks Shihui!