The real Satan's symbol?
The reversed pentagram. It is mostly used for Baphomet. Version of Satan/Lucifer, a goat like creature with male and woman characteristics as angels have no gender :
! Be careful !
So you may wonder what is the real symbol? Well...the reversed cross is not a symbol that represents any dark symbol..the reversed cross resembles Saint Peter's will to becrossed reversed because as he said: "I am not worthy to be punished as Christ did" Even though The Satanic Temple recognizes the upside down cross as satanic it is NOT.
The Leviathan Cross or Satan's Cross. It represents alchemy/satanism in general. Particularly it symbolizes the alchemical symbol of sulfur associated with fire and brimstone of Hell.
There is no real symbol for Satanism. The most widely used and surer to use as a Satanic Symbol is the reversed pentagram and Leviathan Cross.