Sometime in the 15th century, a group of Pilgrims imprisoned Kestrel and her Goblins in a rock crystal then placed it on an Elron Witchcraft Altar for safekeeping. Nearly 300 years later, the altar was disturbed during a construction project for nearby Lewiston Girls Academy. The rock crystal was dislodged from the altar and split in half. Kestrel took one half with her as she planned revenge against her enemies. A few days later, Peter Venkman "discovered" it when he kicked it by accident. The halve was kept in a secure safe in Ecto-1.
However, Kestrel later possessed Egon and learned the crystal's location. She took it and reconstituted the rock crystal in hopes of imprisoning her enemies in it for all eternity. Luckily, she was excised from Egon's body just in time. Egon, in turn, used the rock crystal to once again imprison Kestrel and her Goblins.
When in one piece, the rock crystal can imprison several types of supernatural entities within it forever as long as it is not broken. The crystal has been shown to possess the power to trap Ghosts, Goblins, and Demons.
- On page 19 of Ghostbusters Issue #14, the Containment Rock Crystal makes a non-canon cameo on the table.
- ↑ Egon Spengler (2009). The Real Ghostbusters - "If I Were a Witch Man" (1989) (DVD ts. 13:09-13:11). Time Life Entertainment. Egon says: "It's half of a primitive Containment Unit."