Mycoclown
Mycoclowns, also known as geloshrooms, are a sapient, psionics/psionic fungal species thought to originate from the Infinite Stairwell. They are symbiotic to beings that experience laughter and feed on its mental byproducts directly from the noosphere using their complex mycelia. They vary dramatically in appearance and physiognomy.
While mycoclowns appear to have traditional geometry, they are partly extradimensional, and have a complex relationship with spacetime. They are able to exist many times in the same space (it was once thought to be an infinite number, but this was proven extremely improbable by the experiments of dual-wizards Vorana Ramonia and Ghorlaxa'Devali of Garthan VI in 458PR) and can warp geometry within a variable radius according to their size (extending roughly 5% of the combined length of their mycelium from their entire body) to create an extradimensional space and allow travel to and from such places. They are able to construct semipermanent windows into such "clownspaces" by extending their mycelia. Captured mycoclowns are sometimes forced to effectively become bags of holding in this way, although self-aware mycoclowns are typically very good at escaping from such situations, so they are typically raised from spore without access to any psionic medium through which to mentally develop. Mycoclowns at large find this practice deeply unhilarious.
Clownspaces vary dramatically in size depending on the the size and number of mycoclowns inhabiting them. They have no inherent connection to other clownspaces but clownspaces can be nested as much as necessary.
Although mycoclown methods of inducing laughter are sometimes harmful, they are far more commonly beneficial and are extremely unlikely to pose any threat due to the potential negative repercussions and their dependence on their hosts. For example, while some evil mycoclowns decide to induce nervous laughter, or use tickle torture to force laughter, this is rarely a healthy long-term source of food for a mycoclown, and other mycoclowns will typically intervene as soon as they realise this is happening, especially if the local population was otherwise unaware of their presence. Despite this unlikelihood of malignancy, records do exist of mycoclowns continuously procuring laughter using this method, and it is said that these mycoclowns gradually poison themselves from the "cursed laughter" and at some point transform into a monster known simply as a killer mycoclown, a powerful creature that causes victims to laugh themselves to death and captures their still-laughing spirits in their clownspaces, which are sadistic realms that do not bear thinking about.
Among the innate psychic abilities of mycoclowns is the power to create hallucinatory replicas of scenes imagined or remembered by individuals, and to alter the scenes at will. They possess extremely robust memories, and can hold multiple "simulations" in their minds and perfectly recall them at any point. In some cases, sapient beings work together with mycoclowns to establish permanently accessibly clownspaces that provide a way for anyone to access these simulations. These sorts of establishments are known as "shroomsuites".
Despite their telepathy, they struggle with the languages of wholly three-dimensional beings. For this reason, they have generally shirked from communicating with material beings at large. However, the methods glodes have developed to communicate with fungi have proven extremely effective at forming diplomatic negotiations with the mycoclowns, and they have essentially become their "official" material representatives.