Poker pro Jeff Gross has won more than $1.5 million lifetime in poker tournaments, but he just had perhaps his biggest payday ever thanks to a bizarre prop bet.

According to fellow poker player Dan Bilzerian, Gross and amateur poker player Bill Perkins — who happens to have a lot of money from the business world — got tangled up in a bet that resulted in Gross getting a tattoo on his back and pocketing $550,000.

He supposedly can’t ever get rid of it, per the terms of the bet.