This is a spectacular double denomination involving coinage from two countries. The U.S. Mint struck coins for the Philippines in the 1970ís including the Philippine 1 Piso coin.
It is a large coin and there are few major mint errors known on this denomination. Somehow a struck U.S. Quarter was overstruck off-center by the Philippine 1 Piso dies. It is a spectacular and dramatic major mint error and it is extremely rare.