Spectators had 3‒4 ft (0.91‒1.2 m) bodies, which weighed 250 lb (110 kg). They had four eyestalks, as opposed to the typical ten of normal beholders, with two located on either side of the upper half of the body. A spectator's skin was thick, lumpy, and rubbery, with numerous blood vessels visible on the surface. Like regular beholders, they had a single main eye in the middle of their floating bodies.
Spectators were vigilant and trustworthy, and could be relied upon to protect items in all but the most dire situations. They possessed two methods of behavior: a free-thinking mode and a contemplative mode. Free-thinking spectators would wander the planes at will, openly, if cautiously, chatting with those they came across. In their contemplative state, they were philosophers who would spend over a century pondering vast philosophical questions. Approached in this state they were still friendly and enjoyed discourse but would soon after request to be left alone so as to continue philosophizing. Years of isolation could result in spectators gaining personality quirks such as referring to themselves in the third person or adopting the voice of its summoner.
Spectators disliked guarding things for lesser lifeforms, which most mortal summoners would qualify as, and would only do so hesitantly. After promising to do so, however, their loyalty to their summoner was absolute, guarding the object in question until their time was up. They prided themselves on their guardianship and refused commands to do anything else until asked to guard something else or they were allowed to leave a summoner's grasp. The greatest pleasure for most spectators was thwarting the forces of chaos and in defending valuable objects. A spectator's strong sense of justice dictated that creatures who did not intrude upon their duties had a right to live, and they would never attack a helpless opponent unless attacked via sly or cruel means. Killing creatures for any reason outside of duty or self-defense would lead most spectators to commit suicide in distress via self-imposed brain overload.
Their main eye could turn spells back at the caster so long as they were in the nearby area and shooting at its face. The four eyestalks of a spectator could cause effects like the spells paralyze, inflict moderate wounds, fear, and confusion. They were capable of creating enough food and water to sustain themselves for one day, every day, meaning that they would never go hungry, and could also planeshift once per day.
When trapped within the bounds of a ritual circle created with beholder eyes, a spectator was powerless to use any ability besides levitation.
Spectators were peaceful and would never attack unless seriously provoked. When not guarding something, if they were attacked by any opponent powerful enough to harm them, they would typically flee. Spectators only willingly fought against those who disturbed what they were guarding, those who persistently pestered them, and other spectators. The methods used to repel foes would become more drastic as the battle continued, starting with fear and confusion and escalating into paralysis and enervation.
Though they could planeshift, they would only do so to retreat if injured in all eyes to the point of non-functionality, thus leaving them incapable of guarding their wards. If chased after this point, they would defend themselves by biting at their pursuer. They would return one day after leaving, and in any circumstance, their ward's disappearance would prompt them to return to Nirvana for good.
Spectators hailed from Mechanus and could be summoned to the Material Plane by a ritual requiring at least 4 beholder eyes. Using more eyes would increase the chance of the ritual's success, with 10 ensuring completion. The beholder eyes would be ground into a powder, burnt until the powder was nothing but black dust, then doused with oil, set on fire and placed in a special magic circle. Using the dust as the component a wizard would create a one way gate to Nirvana and call the monster in a way similar to the summon monster spell. Once summoned this way, spectators would be placed in their contemplative condition, and peacefully reside for 101 years in an approximate 100 yard area from where they were summoned to. No one but the summoner and beings stated to be allowed during the initial dealing would be permitted to touch or enter the area it was summoned to guard.
Spectators were organized into an upper and lower class. The lower class resided alone in small vertical caves in the modron disk dug out using their mouths. The upper class worked as guards for important modron and were educated to uphold the lawful ideals of Mechanus. Lower class spectators tended to drift between lawful good and lawful neutral, while upper class were strictly lawful neutral. The only way to become an upper class spectator was to capture and deliver a rogue modron to local Mechanus authorities. The position was not permanent and would be revoked in a spectator's old age when they could no longer fight, forcing them to retire to their caves. High leveled modrons, and even spectators themselves would bargain with the bodies of slain spectators to be used for research by others.
Spectators were smaller than regular beholders and as such required less food, although a full meal for them was still enough to make a large meal for 6 people. They could simply conjure the large quantity of food needed for them to live each day, although they were willing to share with visitors. When spectators slept they drifted aimlessly around a given area.
In the middle of their brains laid a small magical organ shaped like a sphere, that granted them the ability to fly, although it could not be magically disabled. A spectator's brain generated magical energy with psionic power, but was not strong enough to grant it psychic abilities. It created both magical and anti-magical force, with the former used to power its eye rays and the latter used for its spell turning. Spectators possessed a perfect internal clock, able to tell exactly when a certain amount of time had elapsed with extreme precision. Because spectators came from Nirvana, they were best adapted to equal amounts of environmental factors, (light and dark, heat and cold, liquid and solid terrain etc).
So long as they were within Mechanus, spectators possessed a rapid regenerative ability capable of repairing lost structures and recovering from general damage.
Newborn spectators arose from the eyes of their recently deceased 'parent'. Each was born with the ability to levitate, along with the eye ray power of whatever stalk they came from. One spectator had the ability to create food and water and shared it with its siblings. Every 3 months a new eye power would be gained and the spectators would grow larger. After a year passed, each spectator would leave their birth home and create their own lair. Once a spectator became 1,000 years old the cycle would reverse in a sense, with their eyes becoming progressively larger and their body slowly turning smaller at the same points in time that the new spectators would gain eye powers. At 9 months old the spectator would grow 4 tiny eye stalks on each of its old eye stalks and 3 months afterwards would die, causing the cycle to begin anew. Neither newborn, nor elderly spectators could be summoned via the ritual.
Some spectators served certain deities, including Gaerdal Ironhand, Gorm Gulthyn, Helm, and Savras. They were often employed by the Church of Helm, and watched over their temples as ever-vigilant guardians.
- Aloxag: the spectator bodyguard in service of the Red Wizard and an apprentice of Halaster Blackcloak, Ibbalar Thrul in the mid-14th century DR.
In 1370 DR, Waterdeep was briefly plagued by a small army of spectators who were sent there to "guard" powerful and notable enchanted items, such as Khelben Arunsun's Blackstaff and Piergeiron Paladinson's Halcyon. The spectators caused panic and chaos in the city and guarded the entrance to Undermountain. Khelben deducted that Ibbalar Thrul, a disgraced wizard and businessman, was likely behind the attack. He sent one of his agents into the wizard's lair in Undermountain. Subsequently, the summoning portal was sealed, and Ibbalar's attack was stopped.
- Mike Mearls, Jeremy Crawford, Christopher Perkins (2014-09-30). Monster Manual 5th edition. Edited by Scott Fitzgerald Gray. (Wizards of the Coast), p. 30. ISBN 978-0786965614.
- Richard Baker, James Jacobs, and Steve Winter (April 2005). Lords of Madness: The Book of Aberrations. (Wizards of the Coast), pp. 140–141. ISBN 0-7869-3657-6.
- Doug Stewart (June 1993). Monstrous Manual. (TSR, Inc), p. 21. ISBN 1-5607-6619-0.
- Gary Gygax (August 1983). Monster Manual II 1st edition. (TSR, Inc), p. 112. ISBN 0-88038-031-4.
- Dougal Demokopoliss (November 1988). “The Ecology of the Spectator”. In Roger E. Moore ed. Dragon #139 (TSR, Inc.), pp. 86–88.
- Arron Allston (1996). I, Tyrant. (TSR, Inc.). ISBN 0-7869-0404-6.
- Sean K. Reynolds (2002-05-04). Deity Do's and Don'ts (Zipped PDF). Web Enhancement for Faiths and Pantheons. Wizards of the Coast. pp. 10–15. Archived from the original on 2016-11-01. Retrieved on 2018-09-08.
- Eric L. Boyd, Erik Mona (May 2002). Faiths and Pantheons. (Wizards of the Coast), p. 29. ISBN 0-7869-2759-3.
- Interplay (December 1997). Designed by Chris Avellone, Robert Hanz. Descent to Undermountain. Interplay.