A flumph's body was shaped like a flat saucer with a diameter of 2 feet (61 centimeters), slightly larger than a human from shoulder to shoulder, and between 3 to 4 inches (7.6 to 10 centimeters) thick at their center, about as thick as a human arm. The thickness tapered to about 1 inch (2.5 centimeters) at the edge of the saucer. Their bodies were hollow, with a small circular hole at the center of their topside. They had a pair of 6‑inch-long (15‑centimeter) eyestalks on either side of the central hole, as well as numerous tentacles and small spikes that grew from the underside.
Flumphs floated about 4 to 6 inches (10 to 15 centimeters) above the ground by means of an innate anti-gravity field, and moved by using air jets as propulsion. The air circulated through the flumph's body by entering in the central upper cavity and exiting from small holes in its underside and from apertures along the rim of its body. In fact, they were named after the characteristic whistling sound made by these jets, which could only be heard in quiet areas and produced a gentle breeze. Their more peripheral tentacles were very dextrous and were capable of manipulating small objects.
Flumphs were wise and possessed advanced knowledge of philosophy and other subjects. They fed on psionic energy and were therefore more likely to be found near strong sources, such as aboleth, gith, and mind flayer settlements. However, due to their strong telepathic nature, flumphs were very sensitive to evil thoughts and felt the need to share them as quickly as possible with any good-aligned creatures they found, in order to wash these thoughts away.
It was also common for flumphs exposed to evil thoughts to spontaneously glow red in anger. This reaction was considered a sign to adventurers that evil monsters lurked nearby.
Normally, a flumph's reaction when facing an evil creature was to flee. However, flumphs' tendrils were acidic and could be used as defensive weapons if necessary. They also had the ability to shoot a sticky, foul-smelling fluid whose odor lasted for several hours and was potent enough to sicken nearby creatures as well. The fluid could be removed from a victim by spending at least an hour bathing in water, alcohol, or vinegar.
Most typical flumphs led nomadic and monastic lifestyles. Their society was organized in harmonious cooperative groups called "cloisters", in which all flumphs shared knowledge and contributed according to their own skills. Ordinary members of the cloister were called "monks". A typical cloister could be up to 32 monks strong and was led by an "abbot", who was aided by a group of "priors" that comprised about one sixth of the monk population. It was common for monastic flumphs to be capable of casting cleric spells, but the benevolent deities they worshiped were unknown to humanoids.
Cloisters were also known for sometimes recruiting isolated mindwitnesses into their communities. Once a mindwitness was taken in service of the flumphs, it would change its world view accordingly and was no longer an evil creature.
Flumphs were largely ignored by mind flayers, who had no interest in them. For that reason, it was relatively common to find cloisters of flumphs near mind flayer settlements. On the other hand, githyanki abhorred flumphs violently, and attacked them on sight.
Flumphs reproduced about once every two years by a budding process, in which between one and eight tiny younglings sprouted from the adult's underside. The young flumphs became fully independent after three months, upon reaching a diameter of about 2 inches (5.1 centimeters). They then grew to fully adult size after one month. Their lifespan was about 20 years.
Besides psionic energy, flumphs also fed on small vermin such as rats, lizards, and frogs. They hunted by floating about 1 to 2 feet (30 to 61 centimeters) higher and then jumping on top of their prey, immobilizing them and absorbing their nutrients with their tentacles.
Some flumph internal organs could be harvested for practical applications. Their brains, when powdered, could be used in the crafting of potions of levitation, with a yield of three potions per brain. The inner layers of their tentacles could also be harvested to make oil of acid resistance, with every twenty tentacles yielding one serving of oil.
The glands that produced their defensive foul-smelling fluid could be used as a material component for the stinking cloud spell. However, the characteristic smell produced by a spell cast using that component was likely to attract the attention of every flumph within a 1‑mile (1.6‑kilometer) radius.
The origin of the flumphs was ultimately a mystery. It was speculated that flumphs were genetically related to grells or belabras, due to some physiological similarities such as their hovering and the presence of tentacles. Given the probable genetic ties to the grells, most sages agreed that flumphs originated in a different world and traveled as clandestine passengers in grell spelljammer ships.
During the late 1480s DR, flumphs were greatly disturbed by the demonic madness that permeated the Underdark. Some offered assistance to anyone who opposed the derro cultists under Gracklstugh, while a cloister of flumphs from the Wormwrithings maintained that kindness was the only appropriate response during those evil times.
By the Year of Three Ships Sailing, 1492 DR,[note 1] a cloister of flumphs inhabited the Seadeeps level of Undermountain, feeding off the psionic energy of the nearby illithid and githyanki settlements.
- Laal, an erudite female flumph who contacted a group of adventurers to seek justice for the murder of her mate, Xol;
- Xol, an adventurous male flumph who was murdered by the Cult of the Crushing Wave in an expedition to the sewers of Mulmaster.
- The Pink Flumph, a theater in the Castle Ward of Waterdeep.
- Flumph Mating Rituals, a book on the mating habits of flumphs.
- Canon material does not provide a year for the events described in Waterdeep: Dragon Heist, but Christopher Perkins answered a question via Twitter and stated the year was 1492 DR. Corroborating this, Dragon Heist page 20 refers to events of Death Masks (set in 1491 DR) as being "last year". Unless a canon source contradicts this assertion, this wiki will use 1492 DR for events related to this sourcebook and Waterdeep: Dungeon of the Mad Mage (which is referenced on pages 5 and 98 of Dragon Heist).
- Out of the Abyss • Waterdeep: Dungeon of the Mad Mage • The Orrery of the Wanderer
- Referenced only
- Waterdeep: Dragon Heist
- Video Games
- Referenced only
- Descent to Undermountain
- Board Games
- Betrayal at Baldur's Gate • Dungeons & Dragons Adventure Begins
- Card Games
- Adventures in the Forgotten Realms
- Organized Play & Licensed Adventures
- Foulness Beneath Mulmaster
- Mike Mearls, Jeremy Crawford, Christopher Perkins (2014-09-30). Monster Manual 5th edition. Edited by Scott Fitzgerald Gray. (Wizards of the Coast), p. 135. ISBN 978-0786965614.
- Logan Bonner, Chris Sims (April 2009). Dungeon Delve: Fool's Grove (PDF). Wizards of the Coast. p. 8. Retrieved on 2016-12-07.
- Tim Hitchcock (January 2005). “Box of Flumph”. In Erik Mona ed. Dungeon #118 (Paizo Publishing, LLC), pp. 30–31.
- Jon Pickens ed. (1995). Monstrous Compendium Annual Volume Two. (TSR, Inc.), p. 58. ISBN 0-7869-0199-3.
- Don Turnbull (1981). Fiend Folio. (TSR Hobbies), p. 39. ISBN 0-9356-9621-0.
- Jim Zub, Stacy King, Andrew Wheeler (July 2019). Monsters & Creatures. (Ten Speed Press), pp. 10–11. ISBN 978-1-9848-5640-1.
- Johnathan M. Richards (April 1998). “The Ecology of the Flumph”. In Dave Gross ed. Dragon #246 (TSR, Inc.), p. 78.
- Mike Mearls, et al. (November 2016). Volo's Guide to Monsters. Edited by Jeremy Crawford, et al. (Wizards of the Coast), p. 176. ISBN 978-0786966011.
- Christopher Perkins (November 2018). Waterdeep: Dungeon of the Mad Mage. Edited by Jeremy Crawford. (Wizards of the Coast), pp. 222, 224. ISBN 978-0-7869-6626-4.
- Johnathan M. Richards (April 1998). “The Ecology of the Flumph”. In Dave Gross ed. Dragon #246 (TSR, Inc.), p. 81.
- Christopher Perkins, Adam Lee, Richard Whitters (September 1, 2015). Out of the Abyss. Edited by Jeremy Crawford. (Wizards of the Coast), pp. 67, 167. ISBN 978-0-7869-6581-6.
- Tim Eagon (2015-06-01). Foulness Beneath Mulmaster (DDEX2-08) (PDF). D&D Adventurers League: Elemental Evil (Wizards of the Coast), pp. 5, 10.
- Christopher Perkins, James Haeck, James Introcaso, Adam Lee, Matthew Sernett (September 2018). Waterdeep: Dragon Heist. Edited by Jeremy Crawford. (Wizards of the Coast), pp. 74–75. ISBN 978-0-7869-6625-7.
- Christopher Perkins, James Haeck, James Introcaso, Adam Lee, Matthew Sernett (September 2018). Waterdeep: Dragon Heist. Edited by Jeremy Crawford. (Wizards of the Coast), p. 150. ISBN 978-0-7869-6625-7.