The Jade Pyramid was a jewel that was said to beautiful beyond belief, and to hold powers mightier than that of a god. In truth, it was a trap, that was used to catch Melora, the Queen of Spring.
Nook Nimmlock stole the Pyramid and hid it aboard his ship, after hearing his boss, Lady Arnaesis, express her desire to give it to her lover, Melora, the Queen of Spring. He was arrested by the Spring Court guards for unrelated gambling charges, where he met the Feywild Four, and asked them help him break out so that he could get the Pyramid back to Lady Arnaesis, which they did1. The group got the Pyramid and brought it to Lady Arnaesis, only to discover that she was actually Lady Adira Harper, and the Pyramid was a trap for Melora. Adira froze her in place with the "jewel" and opened a massive portal, from which the goddess Lolth emerged2.