Not a stamp, but interesting all the same. According to the site on which I found this image this is:
"BULGARIA NOTE 1 CARP 2001 - UNCIRCULATED
PRIVATE ISSUE (CYPRINUS CARPIO)UNION OF THE HUNTERS AND ANGLERS OF BULGARIA. The ONE CARP notes are fancy collector's souvenir notes, initially issued to commemorate the European Championship for freshwater fishing in Plovdiv, Bulgaria in June 2001. The carps have most of the security features of a banknote as well as a limited total printing".
![Image](http://i45.tinypic.com/2lo1x14.jpg)