A quarter planchet will not fit into the collar used on cent coining presses. It had to have been done outside the mint. The faking of error coins has started to become a big thing, I think most of the time it is just a so-called fun thing and not done to cheat anyone. On the other hand it is done to cheat people. Some one could have heated up the quarter so that the cent would design would go into the quarter. A vice could have also been used. Your coin is not a mint error but just a conversation item.

A picture of the coin, both sides, would help determine how it was made. My guess is it was man made after it left the mint since a quarter planchet can not fit into a press set up for pennies.

those are worth lots of money look on ebay and see if u can find one like yours. they are extremely rare tho. i have a one dollar bill that was cut wrong and its worth over 500 dollars