Frog Claws

http://news.xinhuanet.com/english/2008-05/28/content_8269916.htm

http://www.thaindian.com/newsportal/sports/bizarre-frog-can-break-its-own-bones-to-produce-cat-like-extendable-claws_10053669.html

I can't resist: http://www.youtube.com/watch?v=ftgAG3Vnif8