Cereal Prize Of Death

Basically it was a tiny spinthariscope: when the red tail fin was taken off, you could look through the ring and observe some scintillations caused by nuclear reactions of polonium-alpha particles on a zinc sulfide screen. One million rings were made, and these were the most popular premium rings ever.

(click to enlarge)

 

Polonium is highly toxic and radioactive. One grain of the stuff can kill you in the most horrible ways. The KGB used some to kill an opponent of Putin's living in London. He was reporter and they stuck him with the sharp end of an umbrella coated with the stuff. I think he died three weeks later.

 

So have fun kids.

 

https://en.wikipedia.org/wiki/Poisoning_of_Alexander_Litvinenko