Pentagram
Some Satanists, especially members of the Church of Satan, use an upside-down pentacle as a symbol for their religion. The Church of Satan's official symbol is an upside-down pentacle with a goat head inside, called the Sigil of Baphomet. (A 'sigil' is a symbol of a supernatural being). It was originally the influential 1800s French occultist Eliphas Levi who associated the pentagram with the goat-headed baphomet, by drawing a pentagram on the baphomet's forehead. Anton LaVey, who created the Church of Satan in 1966, took the idea from Levi.