Incorporeal undead are one of the four major types of undead. This type of undead is the closest linked to the Negative Energy Plane. The core of their being resides there, making them seem intangible when seen on the Material Plane. Examples of this type of undead are ghosts, spectres and wights.
- Dennis Baker et al. (2014). Undead Slayer's Handbook, p. 4. Paizo Inc. ISBN 978-1-60125-604-1
- Dennis Baker et al. (2014). Undead Slayer's Handbook, p. 5. Paizo Inc. ISBN 978-1-60125-604-1
- Todd Stewart. (2009). The Great Beyond: A Guide to the Multiverse, p. 3. Paizo Publishing, LLC. ISBN 978-1-60125-167-1 . This book suggests ghosts and spectres reside on the Material Plane, corrupted by negative energy but tethered and prevented from entering the Great Beyond.