Inverted cross: The Cross of St. Peter or Petrine Cross is an inverted Latin cross traditionally used as a Christian symbol, but in recent times also used widely as an anti-Christ symbol
The origin of this symbol comes from the Catholic tradition that Simon Peter was crucified upside down, as told by Origen of Alexandria. The tradition first appears in the "Martyrdom of Peter", a fragmented text found in, but likely predating, the apocryphal Acts of Peter, which was written no later than 200 A.D. It is believed that Peter requested this form of crucifixion as he felt he was unworthy to be crucified in the same manner that Christ died (upright). As such, some Catholics use this cross as a symbol of humility and unworthiness in comparison to Christ.
It has also often become associated with Satanic and anti-religious attitudes, as it is considered to represent the opposite of Christianity by inverting its primary symbol, the Latin Cross. As a result, this symbol has become very popular within anti-religion groups and among some extreme metal musicians, notably black metal groups. In popular culture, including films such as Rosemary's Baby, Exorcist: The Beginning and The Omen, Petrine Crosses are often displayed to represent Satan. Coincidental with this Satanic imagery, not only is Saint Peter the source of the inverted cross symbolism in Christianity, but Jesus once referred to Peter as "Satan"
also can be found in earrings, rings, necklaces and clothing