A Space rat is the common name for any type of rat that finds its way onto a starship.
The bane of most Terran engineers, the creature live in starship ventilation systems stealing rations and chewing through wiring. On richer worlds and stations, space rats are rare or easily exterminated before starships are cleared to leave. The more poorer fringer worlds and lawless stations have a harder time containing the vermin as their populations tend to grow quickly.
Exposure to Vespene gas in some species has lead to the deaths of most. Others that survive mutate and grow to sizes rivalling house cats to mountain goats. Some even grow extra limbs, eyes, and in some situations glow in the dark. To deal with the ones that manage to get on board, larger vessels deploy a type of laser defense that sweeps the vents regularly before being cleaned (Beast Wars: Sentinel; Resident Evil: The Hive). Those who cannot afford such systems, such as low level smugglers, have to hunt the creatures down personally or risk having essential systems chewed apart.
Some underworld gambling places even commission certain exterminators, hunters and traineers to bring some to use a entertainment in gladitorial or racing events (Star Trek - DS9: Cardassian vole; Mass Effect 2: Varren).
- Duct escape (passive) - critter disappears into machinery if attacked. Only works if critter is in an installation or starship
- Short circuit (autocast) - critter disables nearby turret, doorway, or airlock