My aunt's beagle is a demon?

Okay so I'm dog sitting for my aunt while she's out of town and her beagle puppy is awful! She shits in the house, gets on the table, and chews everything in sight! Whenever I try to take something she's not supposed to have, she growls and barks at me. And when I hit her with a rolled up newspaper, her eyes glow red and she growls. Then she whimpers and goes to lay down. How do I tell whether she's a demon or just demon-possessed? And if she's demon-possessed, how do I exorcise her? And if she's a demon, how do I tell my aunt?