Dog is unresponsive

UPDATE: After re-starting the world, the dog was able to return to normal.

Recently, I noticed that my dog would not follow me, even though I didn't make him sit. I found him, and he was looking at the ground. I checked underneath my house to see if anything was there, but there was nothing. I tried to attach him to a leash, but he would not come. I also tried standing where he was, and he didn't move. I then broke the two blocks he was standing on, but he was floating in the air. Finally, I tried to pull out some cooked beef, and he tilted his head, but it wouldn't work half of the time. I don't know how this happened.