Osiris and Riff Rat are an unusually trusting couple; the 3-year-old Dutch shepherd therapy dog lets the 3-month-old rat crawl into his mouth and clean his teeth – Dutch shepherds are famous for their obedience and train-ability. Riff Rat was rescued at an early age and nursed back to health, and now the two are inseparable. Check in with their popular Instagram account HERE for more of their unusual friendship.