Nightmares (3.5e Trait)
From D&D Wiki
Sometimes after a long day your body is stressed and your mind is ready for rest but the plane of dreams denies you access and you are shunted into someones nightmare.
Benefit: Because you are denied a peaceful sleep your body has become used to not getting a lot of sleep. You now only need 4 hours of sleep and are immune to the affects of the spell sleep. In addition your nightmares are so powerful they start to invade upon the waking world. While you are in combat there is a 10% cumulative chance per round that you cast Nightmare as the spell with the target being the one you are attacking.
Drawback: During combat there is a 5% cumulative chance per round that your nightmares become real and attack you. Treat this as the Nightmare spell with you as the target. Finally if you are ever knocked unconscious you lose all control and everyone around you is danger. You must make a will save or every one around is the target of the Nightmare spell.
Roleplaying Ideas: Should allow in games with the plane of dreams in your cosmology