Satanism is comprised of those who follow Satan, rather than Christ, and many symbols are variations of Christian symbols, just like most beliefs are direct contradictions of Christian beliefs.
The Satanic Bible was written in 1969 by Anton LaVey. His book, and subsequent church and teachings, is the basis for many ideas about Satanism, but the symbols of Satanism are usually very old and steeped in other traditions, like pagan, occult, and Wiccan. Although some people believe Wicca is the same as Satanism, or the worship of Satan, it is actually a religion founded on traditional pagan believes that is unrelated to Christianity. Satan, the Devil or Lucifer, is the chief evil spirit or demon, according to standard Christian theology. Satanism is comprised of those who follow Satan, rather than Christ, and many symbols are variations of Christian symbols, just like most beliefs are direct contradictions of Christian beliefs.
Unlike the Bible, the Satanic Bible is supposedly written entirely without divine or supernatural inspiration, according to the author. Weirdly enough, much of the Satanic Bible is not worshiping of Satan, as the name would imply, but worshiping of oneself as god, with the ultimate goal of reaching a godhead. Basically, Satanism upholds values that are contrary to every value held by mainstream, “white-light” religions, primarily Christianity. The pentagram is a five sided star drawn with a continuous line. Also known as the pentacle, this symbol has a long history outside of Satanic traditions and beliefs. The symbols is used a magical object or talisman, often symbolizing earth. Because there is widespread diversity in those who believe this symbol has mystical or supernatural powers, the symbol can mean very different things. Some people believe that a pentagram is a sign of the element of earth in Wicca, but when a circle encloses it or when it is inverted it becomes a sign of Satanism. According to some sources, a pentagram tattoo marks the person as bound for hell. This tattoo is often meant to honor Satan and procure the bearer a better place in Hell.
Some traditions maintain that a pentagram on the stomach of a woman means that any children she has will be offered to Satan in exchange for a higher position and more authority. Other sources maintain that the inverted pentagram tattoo symbolizes a person drawing power from beneath, or inside depending upon person beliefs, in order to find their inner god. The inverted cross is perhaps even more controversial. Simply put, the inverted cross is a tradition Roman Catholic, or Latin, cross that is flipped, so the cross bar is close to the bottom rather than near the top. On one hand, some people believe that this symbol is a mockery of Christian theology, meant to trivialize the death of Jesus and represent adherence to Satanism. On the other hand, the inverted cross is also representative of the death of Saint Peter, who was martyred.
Saint Peter, the Bishop of Rome (which is where the position of Pope originated), was crucified upside-down because, if the story is believed, he felt unworthy of dying in the same manner as Christ. Known as the Petrine Cross or Peter"s Cross, the inverted cross is a significant symbol used by the papacy. It is not a satanic or disrespectful symbol. Contrastingly, the inverted crucifix, or an inverted cross with Jesus on it, is thoroughly offensive to the Catholic church. The inverted cross is only recently associated with Satanism, made even more popular by Hollywood films and pop culture portrayals. Some adherents of Satanism or those who wish to disassociate themselves fully from Christian values embrace a 666 tattoo. According to the book of Revelation, this mark will appear on the the followers of the Anti-Christ. It is called the number of man or the mark of the Beast. Obviously, this is a very anti-Christian symbol for a tattoo. However, there is no coherent or organized use of the three numbers and no religious organization claims the symbol as their own. It is primarily used sporadically by individuals protesting Christianity and desiring to display their personal aversion to Christian theology, or organized religion in general. There are many other symbols that are associated with Satanism, but most of these associations are incorrect. Swastikas, anarchy symbols, stars and moons, serpents, the zodiac, the peace sign, and asian symbols are not connected to the Church of Satan or satanic rituals. These symbols have many, many meanings and deep cultural significances. They are not representative of the Devil. In fact, they are often representative of ancient religious beliefs or philosophies completely unrelated to Christianity. Many of these supposed signs of Satan came about due to misinformation and panic in the 1980s, dubbed the "Satanic Panic".