On the back of the later Series 1 "Secret 12-Pack" (US)
was an ad for a special Series 1 monster which was
included randomly in the packs. This could be identified
with a star on its back instead of a point value.
Here is the text from the ad:
Keep your eyes peeled!
If someone knows if such a secret monster has ever
be found please let me know. Also if you would even
sell one.
And win a mystery grab bag of
Monster In My Pocket toys!
Hidden in one of every 10.000 Matchbox
Monster In My Pocket packages, is a secret
monster which has a special star branded on it´s
back (*) instead of the usual point value. If you
capture it, send it to the address below and we´ll
return it with your Mystery Grab Bag of Monster In
My Pocket toys retail valued at over $50!