I found these nar-lak japanese egg moulds in "Neo 3" (the name of the shop), Imperial Shopping Mall, for 60 Baht. They're for making rabbit and bear shaped eggs for bento boxes. You put a hot freshly boiled egg into the mould, squeeze it shut, then drop the closed mould into cold water. So cute, but Japanese mothers must have far too much time on their hands!
See the resultant egg below, I'm sure I can get a better result with practice and perhaps an L egg instead of the XL egg I used, as the egg spilled out of the side a little!
A map to Imperial Shopping Mall is below, please come visit my blog Appon's Thai Life, for many more odd things of no importance!