Duo-dimension

Duo-dimension was a common spell used by wizards across Faerûn and by wu jen in Kara-Tur.

Effects
The spell created a form of invisibility by altering the caster's dimensions so only their height and width were visible, essentially turning the caster into a two-dimensional being. This unique form of invisibility was detectable by only a true seeing spell. The alteration was physical so a caster was able to travel though extremely narrow spaces, depending on the height of the caster. The spell did not limit the movement or abilities of the caster.

When the caster was visible from the side, they were vulnerable to attack. When a caster used this spell, a portion of their spirit was partitioned onto the Astral Plane and was vulnerable to creatures of that plane. As such, there was always a risk the spirit of the caster would be pulled completely into the Astral Plane.

Components
In addition to verbal and somatic components, the spell required material components: a piece of the finest ivory in the likeness of the caster, studded with gems and lined with gold worth between 500 gp and 1000 gp, and a piece of regular parchment. As the caster uttered the verbal component of the spell, the parchment was joined at both ends that created a loop and the caster passed the ivory figurine through the loop. This spell was quite expensive since both material components disappeared on successful casting of the spell.