Upon activation, 1d4 characters in the party, at random, must make a Saving Throw vs. Magic, or be hit by a beam of light that causes them to shrink to the size of an average person's thumb!
The character's weight, strength, clothing, armor, weapons (along with associated damage), and all other carried items shrink with them accordingly. Magical abilities, such as spell damage or range, do not change (they don't call it magic for nothing), but affected characters are now small enough to be carried around easily in a full-sized person's pocket.
This effect will last until Dispelled, or until the characters leave the dungeon.
Optional: This effect is permanent until magically cured.