Nari'hog

You find a lost, gaunt Sangheili hiding in an abandoned building who has somehow been teleported from his planet to Earth. You give him free lodging in your home while you figure out how to communicate with him and what to do with him. One day, after deciding that you're going to keep it hidden in your house from everyone else, you get some KFC and take it home to eat it. He wants some, so you give him some. Thus begins his addiction to KFC, now every day he asks for more and more KFC. If you refuse to bring him KFC, he gets angry and throws a tantrum, so to keep him calm you submit to his demands. Fast forward a couple of months, and now it's an immobile stain in your living room. It stinks, takes up a lot of space, constantly nags you for more food, and makes life pretty difficult at home. Now you wonder whether to ask someone else for help, report him to the authorities, or continue feeding him so he's less of a nuisance