What is this olden round thingy? (Not a Competition.)

Coin weighs 15.9 grams. Its very hard to see but there is a left facing brittania on one side.

I think it may be an 1806-1808 George III penny. These were the first issued after the Cartwheel pennies and weighed 18.9 grams. Allowing for wear and holes this is about right.

Could well be a Chinese Slave token, (thanks Rbm for explaining the notches) but it may have had another purpose. Some people were known to nail pennys to the floor or above doors to keep out evil spirits. Another superstition was to put a penny at the front door of a newlyweds' house to bring good luck, but horseshoes were more commonly used for this.

Thanks for all help.

 

I would get it out of your house as quickly as possible, it is whats known as a "Alien Love Token".

When an alien finds a human that they like to probe they insert these under the skin at the base of the skull, this one has likely come loose due to over-probing.

You have been warned.