The Floating Crystal of Eoam

(MAJOR SPOILERS FOR THE FORK THE WITCH AND THE WORM, AS WELL AS ERAGONS GUIDE TO ALAGAESIA.) Eragon and Saphira travel to the Floating Crystal of Eoam after strange reports of it causing strange occurrences on the island. Tales of death and shadows, and people that go missing... Are these the shadows that Solembum warned him about?