Advent Ghost #16: Ghost-ridden Scroll/Ghost in the Spell

A Ghost-ridden Scroll

Sometimes a ghost is accidentally (or purposefully) transcribed into the very text of a spell. This traps the spirit until the spell is cast. If a wizard copies the spell into their spell book, the ghost is copied along with it.*

When cast for the first time, the ghost is released along with the spell. A Monster Reaction Roll is made to determine the ghost's behavior. If the PCs are in combat, the ghost could aid them on a positive roll, drift away on a neutral, or join the fight against them on a negative result of that roll.

The Ghost in the Spell

These ghosts appear as a semi-transparent human covered in magical sigils, runes, and text.

AC 2 [17] HD 6* (27 hp), Att 2 × touch (1d6) or Cast Spell, THAC0 14 [+5], MV 120' (40’), SV D10 W11 P12 B13 S14 (6), ML 9, AL Chaotic, XP 500, NA 0, TT NA 

• Undead: Make no noise until attacking. Immune to effects that affect living creatures (e.g. poison). Immune to mind-affecting or mind-reading.
• Mundane weapon immunity: only harmed by silver or magical weapons.
• Cast Spell: every other turn may cast the spell they were transcribed with. If the spell used is not one able to be used in combat, ignore.

If the spell was copied into a spell book*, what happens to the written spell when the ghosts escapes? Roll 1d8 to find out.
1-4 Ghost transcription is erased leaving just the spell.
5. Ghost transcription is erased and ruins the spell. It will have to be researched and relearned.
6. Ghost transcription is erased and the spell changes into another spell. (Randomly determined)
7. Ghost transcription is erased along with the rest of the spell.
8. Ghost transcription remains and summons a copy or the ghost every time the spell is cast.

*This might be more of a house rule thing and not RAW OSE.