Also known as: 逆十字
An upside-down † symbol, generally a Latin Cross. Also called St. Peter's Cross.
It's erroneously represented and currently used to symbolize Satanism or anti-Christianity since the 19th century by an atheist group. It originally represented the Christian legend of how St. Peter was crucified upside-down because he felt unworthy to be crucified in the same manner as Jesus Christ.