Heptagram

The protective circle used to trap Meg in Devil's Trap contains a Heptagram (also known as a septagram, septacle, or seal of babalon), with a hexagon, two circles. The scorpion in the centre is the fifth pentacle of Mars, about which the Key of Solomon says: Write thou this pentacle upon virgin parchment or paper, because it is terrible unto the demons, and at its sight and aspect they will obey thee, for they cannot resist its presence.

The protective circle in Sam's copy of the Key of Solomon.

A Heptagram is a seven-pointed star drawn in one continuous line, in the manner of the five-pointed Pentagram. It can be found in the holy seal of the Brotherhood of the Silver Star, and its history as a protective design has led to the the seven-sided shape of most sheriff's badges.

The Heptagram is also found in Western kabbalah, where it can be a symbol of the seven notes of music, the seven colours of a rainbow, the seven planets, the seven alchemical metals, the seven days of the week, and the sphere of Netzach.

Wiccans of the Faery tradition and the Blue Star Wicca tradition also consider the symbol sacred. In more recent years, Otherkin have adopted the design.