Shimmer script

"Shimmer script" was the name given to a cantrip

Effects
The shimmer script spell made magical writings impossible to clearly read using a wizard eyes spell or other form of scrying, for the purposes of casting, copying, or memorizing. It applied to both the incantations and to the glyphs, runes, and symbols. It could be cast on either the ink that would be used to write the spell, on a freshly written spell.

History
Inhil "Hurler-of-Stars" Lauthryn, the Magister from 154 to 1294 DR, had a special love of blowing up castles, a hobby that had many others spying upon him. He developed the shimmer script spell to conceal his spells from them.