What's wrong with your dog?

1. It emits bursts of radioactivity at random.
2. It swears allegiance to no master but Belphegor, Lord of Hogs.
3. It sometimes no-clips into the walls and floor, jittering, whining, and looking at you in panic. You cannot help it.
4. It compulsively eats parts of itself which regrow overnight.
5. It knows everything there is about late 18th century moon-man architecture and constantly attempts to apply this knowledge in inapplicable situations.
6. It watches you at all times. Even as it eats, or fetches sticks, or attacks an enemy, its head is always contorted at an awkward angle to gaze only at you. It does not sleep.
7. Instead of barking, it just whispers the word "Bark". 
8. For reasons of its own, it is conditioning you to ring a bell every time you feed it.
9. In motion, it looks normal. When at rest, it loses it's internal consistency, slowly oozing and melting into a puddle until it moves again and re-solidifies. 
10. Whenever it's surprised it explodes into a dozen round miniature dogs that roll around barking helplessly, only reforming once it's calmed down. 
11. It stalks you online and creates dozens of sock-puppet accounts that bombard you with false perspectives, slowly warping your world-view to coincide with it's pro-dog agenda.
12. While you're at work it goes into the basement and excretes a noxious saliva that solidifies on contact with the air. It is slowly creating a coccoon. When it is complete, it will wait until you fall asleep and drag you inside.
13. It endlessly vomits up lost relics from the future and the past, then eats them again.
14. It has long conversations with your mother on the phone. She doesn't want to talk to you anymore. "Can you put the dog on?" They laugh about you behind your back. 
15. Flickering dog after-images follow it wherever it goes, like its form has been burned into your retinas.
16. When you look directly at it, you can't see it. You have to unfocus your vision or look at it out of the corners of your eyes.
17. It has lost a fortune of your money gambling on the stock exchange and swears it just needs a small loan to get back on top.
18. Its tail is long, thin, and pulsating. It connects the dog's body to something you can't see in the earth. When it opens its mouth, the barking comes from somewhere deep underground.
19. Every year another family members dies, and every year the dog digs up the graves and buries it somewhere underneath your house. The bone hoard grows. 
20. Whenever you try to warn someone about it, you can't get the words out. Instead, you find yourself talking endlessly about how much you love your dog. Your eyes look terrified, but your mouth says He Is A Good Boy. You notice the same frightened look in the eyes of your friends and family. Look At Him. What A Good Boy, they say. He Deserves A Treat, they say, as it slowly absorbs their hand.