Secret page

Secret page was an alteration spell that hid the contents of a page behind the appearance that something else was written on it.

Effects
Upon casting the spell, the user determined a command word that could reveal the secret contents and then return the page to its disguised state. Speaking the command word twice ended the spell altogether. A page affected by secret page was impervious to spells such as comprehend languages. Moreover, spells such as confuse languages and explosive runes could be cast on it, but only affected the false text. Erase was also ineffective: it destroyed the entire writing. Only a combination of true seeing and comprehend languages could bypass the illusion.

Components
The spell required verbal, somatic, and material components. The materials required were a powder made of herring scales and the essence of either a boggart or of a will-o'-wisp.

History
The spell was attributed to the Netherese arcanist Ptack in −503 DR and was originally called Ptack's secret script.