Jemons

A jemon (also known as a 'demon', a 'daemon', a 'jaemon', a 'jinx', among other names) is a spontaneously occurring hyperspace entity that primarily feeds off of the life energy of material beings. Attracted to emissions from ships passing through hyperspace, jemons remain a constant threat during interstellar travel due to the risk they pose to a ship's crew. Automated or manual security systems are frequently employed by spacecraft in the event of a jemon incursion past the hall. Sufficiently large or powerful jemons may also endanger the integrity of ships themselves, either through sheer size or through the discharge of superheated plasma jets. These jemons are known as "high jemons", and are often known with great notoriety among veteran space sailors. A sufficiently powerful jemon may breach hyperspace and access standard space, posing a danger even without the involvement of hyperspace. 

Jemon size, strength, and cognition vary greatly, with some jemons as small as a few millimeters across and others being planet-sized or larger. Most commonly, they are between two and twelve feet in height and can take a variety of forms. Humanoid and arthropodal forms are most commonly employed by jemons due to their versatility, but tetrapodal, cephalopodal, radial, and combinations of any of the previous have also been documented. The typical jemon has a cognitive aptitude comparable to an ant or honey bee, though jemons capable of sophont-level reasoning are not unheard of and remain a particularly notable threat due to their advanced intelligence. In all cases, individuals are advised to treat all jemons as major threats even if proven otherwise, as the risk of falling victim to a jemon's ruse is an intolerable one.