Well, I would not say it is a prank. If you have the time you can click yourself through all 904625697166532776746648320380374280100293470930272690489102837043110636675 pages and you will find every private key to a bitcoin address you want
This issue was discussed several times here. For sure, it is possible to create same keys but it is very very very...very unlikely. Even with quantum computers it would last decades.
To make you a little bit more afraid, just visit
www.directory.io for example
Yea, I see that site before.
Its only a prank