You shroud an area in illusory dreamstuff, making the ground look and feel like a deep mire or quicksand. Ground in the area is difficult terrain.
Each creature in the area when the spell is cast, or that enters the area, must attempt a Will save. On a failure, it believes it's being pulled down by the earth, taking a –10-foot circumstance penalty to its Speeds. On a critical failure, it's also Immobilized. In addition to the normal actions to Escape, at the end of an affected creature's turn, it can attempt a Will save, removing the effects on a success. On a critical success at any Will save made against oneiric mire, the creature fully disbelieves the illusion and no longer needs to make Will saves to risk a Speed penalty or being immobilized, though the area is still difficult terrain.
Traits
An action with this trait requires a degree of mental concentration and discipline.
Effects and magic items with this trait involve false sensory stimuli.
You must physically manipulate an item or make gestures to use an action with this trait. Creatures without a suitable appendage can't perform actions with this trait. Manipulate actions often trigger reactions.
A mental effect can alter the target's mind. It has no effect on an object or a mindless creature.
A visual effect can affect only creatures that can see it. This applies only to visible parts of the effect, as determined by the GM.