its not yours and for sure the one who owns that bitcoin will do anything to look for who received that amount , so extend your hands reaching for who have wrongly sent you that bitcoins and give them back or else your life might be in trouble and you don't know that this owner will be generous to give you more than what you are asking .
It was his fault and how do even find the owner
Your just looking for justification of how you don't wanna bring it back , because you can just easily send back to the same address that have sent you right?
but of course you will not agree on that because you don't wnat to bring it back .