Third Place Winner in the Spelljammer Creature Challenge!
'Roid jumpers are small rodent-like creatures that inhabit small wildspace earth bodies (and water and air bodies with solid areas for them to live on). They are never found on any planetoid larger than mid size C (around 650 mile diameter) unless introduced through unusual means. Apparently their innate teleport-like ability is not usable on larger worlds and they will lose this ability within 3-5 generations of being introduced to such an area.
These odd relatives of rats have a very unusual ability that many sages have attempted to explain and many mages have attempted to copy: they can teleport safely to nearby asteroids that they've never visited before. Some of the researchers have suggested that they can actually feel the presence of a nearby asteroid in some manner but this is unproven. 'Roid jumpers can teleport from any mid-range size C or smaller world to any other world of similar size. They can even teleport onto passing spelljammers, though the ship must be moving at no greater than tactical speed. The 'roid jumpers apparently have no control over what they actually teleport to because they are just as likely to jump to void earth worlds as to fire worlds as to inhabitable worlds. They are found in asteroid fields in sphere throughout space (including the Astromundi Cluster) and it is speculated they can even teleport to other spheres. They cannot teleport into, out of, or within the phlogiston, however, and lose their teleport-like ability within one generation if introduced into the phlogiston. As they need at least 3 days to recharge so they can jump again they will die if they end up on too many barren asteroids in a row or in a hostile environment. They cannot teleport in response to combat but only in response to population pressures. When teleporting they always travel to other worlds, never remaining on their current one (though a subsequent teleport may bring them back).
'Roid jumpers only fight if cornered or extremely hungry. Due to the isolated nature of the areas they inhabit they have less chance to encounter disease than normal rats but they can carry any disease they encounter just as easily as any rat does.
'Roid jumpers live in small packs, ranging from 2-5 jumpers to almost 100. Packs wil split into two or more smaller packs if they get larger than this, usually with at least one of the packs using their teleport-like ability. 'Roid packs operate closer to canine packs in social structure than they do to rat packs. An alpha male dominates the pack and will mate with any female he desires. The first to produce a litter has the only litter the pack will support until they are fully grown, whereupon another litter is produced (female 'roid jumpers are fertile at all times from maturity on until death just like males). 'Roid jumpers that violate the ways of the pack are exiled (possibly teleporting) and ones that can't keep up are left behind. In this case they operate more like territorial rats, however, and are rarely nomadic (other than when teleporting). Their chief purpose is to find food. Packs will eat anything though they prefer carrion when they can get it (it's easier than fighting for or chasing down a meal). On inhabited asteroids and ships they live much like their rat cousins though the two species are deadly enemies and will fight to the death whenever they encounter each other.
'Roid Jumpers will strip a world bare, almost. As food starts to become scarce they will teleport away, avoiding completely destroying the local ecosystem. Nevertheless, their presence will severely ravage it while they are there. They fill the same niche as most other scavenging rodents (namely rats) do on other worlds. They steal eggs, consume carrion, and dwell in refuse. They are one of the primary bases of life in space and are eaten by most anything carnivorous just as they will eat most anything. For some reason they will never become cannibalistic, however.
Many mages would like to develop a spell that mirrors the teleport-like ability of the 'roid jumpers and these wizards track down specimens wherever they can find them. It is rumored among many spacefarers that early dwarves had magics that allowed them a similar means of travel but was limited to jumping from earth world to earth world.
