There/Not There

This spell creates random fluctuations in the probabilities of the existence of nonliving objects within a 10-foot cube for 10*1d6 minutes. Objects in the area of effect either remain normal and visible or they disappear (50% chance). The state of existence for any object is determined randomly and changes with each viewing and viewer. Therefore, a single object could appear and disappear during the course of the spell, and might be "there" for one onlooker but "not there" for another.

For example, a wizard casts this spell on a doorway. A roll is used to determine that the door is "there" for the wizard, but "not there" for the wizard's companion using a separate roll. The pair study the door for a small while, during which time the door does not change (this counts as a single viewing for each character as they do not look away for this time, and blinking does not count as looking away). After closing their eyes briefly, the two look at the door again, which appears as "not there" for both characters. The pair can step through the open archway to look at the door once again. This time it is "not there" for the wizard, but is "there" for their companion. This random changing continues throughout the duration of the spell

Objects that are "there" are normal in all respects. Doors can be opened, chests can be picked up and carried, and rocks can be used as barricades. Objects that are "not there" are gone, although their absence does not cause any damage, such as ceilings collapsing for example. A viewer could walk through a "not there" wall without difficulty.

When two parties perceive an object in the spell differently, the objects functions for each party according to its own perceptions. For example, a wizard hides behind a rock that they see as "there". Their enemy, a fighter, perceives the rock as "not there" and fires arrows at the wizard, but failing to successfully hit. The wizard would perceive the arrows as bouncing off the rock, while the fighter would perceive the arrows as missing their target or falling short. If the fighter must look away from the rock to knock arrows, they are subject to a check before firing each arrow to determine whether or or not their perception changes.

After the spell is cast, any objects removed from the area of effect retain their uncertain existence for the duration of the spell. Thus, a pair of heroes could pick up a treasure chest, carry it down the hall, set it down, and discover it had vanished while their backs were turned; worse still, one might see the chest and the other could not.