Womp rats were weird brown rats the size of dogs and the most disgusting things in the galaxy. They were worse than Plunk droids. Covered in fleas, ticks, trash, and a five-inch layer of dirt. The odors were killer on the nose, literally. Armies would harness the odors and bomb enemies with them, killing most instantly. The only man known to survive was Acky because he once breathed in stout for nine months. That man had lungs of iron.
Womp rats were native to the planet Tatooine. They were hunted by most of its native people. Some people organized womp rat fights, which was illegal, but no one enforced the rule, due strictly to the fact that womp rats bred like... animals.
Wimp Luke Skywalker used to hunt them in his car (which was sad, because cars weren't even being kept in museums anymore) but he sucked at shooting them. More than once was Luke dragged from his car by a womp rat and ripped to shreds. He somehow survived.
Though native to Tatooine, womp rats were also found on Tatooine II and Coruscant. They traveled to these planets through their own ways of space travel. A group of about fifteen rats would gather together and form a toxic gas bubble that would carry them through space to the respective planets.