D&D: Idea for a cool event - Writing On the Wall

I can see this leading up to something cool: 

Origins of "The Writing On the Wall" here:

"In the Biblical story told in Daniel 5, the haughty King Belshazzar throws a big party. While everyone is feasting, a disembodied hand appears and writes a warning on the wall. The term is also used in the form handwriting on the wall."  <- via the Wordsmith guy/website/emailer.