I found a very thin 2003 10 cent coin. See images below showing both faces and an image of it on top of a standard 10 cent coin. As can be seen from the images it is much thinner and its diameter is slightly smaller than a standard 10 cent coin.
I have had a brief look online (noting I have never researched coins before) and I was unable to find anything similar. I am rather curious what could have caused the coin to be so much thinner and if anyone has seen this before? I thought maybe it could be counterfeit but I am not convinced counterfeiting a 10 cent coin is worthwhile.