I'm not sure if this has ever been implemented yet, but can you imagine a way of paying with Bitcoin by just using your own body?
It would be more of like a microchip implanted into your left or right hand that would contain both your public and private keys to send and receive Bitcoins.
So in case you want to send or receive some BTC, you would just pass your hand over at a scanner and it would perform the desired operation. This is would make it a very convenient and easy way to transact, and carry your Bitcoins with you anytime, anywhere. However, the only thing to be considered would be the security of your private key from within your implant, to protect your funds from theft.
Nevertheless, I want to know your opinion about this, since it would be pretty cool to have such a system to help spread mass adoption of the cryptocurrency.

As in now days I already see some people in the new who started implanting chips in there body and they can use them to pay in stores with just waving there hand the a machine will detect the chip implanted in there hand and hes already paid in what he buy..,,
As now we are not sure if they will use bitcoin as the currency or wallet of the implanted chips but in the book of bible it is already ready happening and it will happened in the revelation..