One of the most widely known Satanic symbols is the inverted pentagram, which can be used to represent Satan as the goat of the Sabbath. Prior to this symbol's gaining wide adoption within Satanism, one of the most popular symbols was the inverted cross; however, this symbol may also be associated with Saint Peter, who was allegedly crucified upside-down by the Romans.
The inverted pentagram, also known as the "Sigil of Baphomet," is the primary Satanic symbol and was noted in rituals for demonic summoning prior to its adoption by the Church of Satan. According to some literature, the pentagram was a symbol for humanity aligned with God's plan, and inverting the symbol so that two points face upward symbolizes perdition and blasphemy. The symbol also contains the Hebrew word "Leviathan" in concentric circles around the inverted pentagram or goat head.
Another Satanic symbol that is less commonly used is the alchemical symbol for sulphur, the smell of which is often associated with Hell. While the number "666" is also sometimes considered a Satanic symbol, it is actually derived from the numerological value of the name of Emperor Nero. It is mentioned as the "number of the beast" within Revelations, however, so many associate it with Satan or the Antichrist.