Thwomp rats were cinderblock-like creatures with curly rat-tails. They could be found on Tatooine, lava planets like Mustafar, and ancient stone castles and temples... like Sith tombs and such. Luke Skywalker used to bullseye little tiny womp rats, but he couldn't even scratch a thwomp rat. A thwomp rat would've crushed him and his little landspeeder. Mario, on the other hand, killed dozens of thwomp rats. The trick is to use a Starman, a raccoon tail-swipe, or Force lightning.