Crazy Dog???

For the past week my parents dog has been going crazy. He got in their tub and knocked over some flowers. He jumped up in the pantry and tried to eat a cake mix. He has been going to the bathroom all over the house, especially the living room where he never goes, and he hasn't been left alone in the house. Then he started destroying the carpet trying to claw his way out of the sliding glass door. He knocked his water dish over a couple of times too (totally not like him). Really, just crazy. It has been driving my parents nuts, so they made an appointment to get him checked out and see if he really is crazy. They even contemplated the possibility of having to have him put to sleep.
Last night they went to bed. The dog was in bed with them, the door was shut, and the alarm was on. About 12:30 someone starts playing the piano. This of course scares them to death. My dad gets up to scare off the intruder. He turns on the hall light and the piano playing gets faster. As he comes around the corner to see who is playing the piano, he finds and opossum. Not a baby, a big one...bigger than the dog. He gets a duster and starts running around trying to scare it out of the house (in his underwear). I really wish I had pictures. The opossum ran all through the house, over the computer, through the kitchen, into the guest bedroom, into the crib, (hissing at my dad the whole time) before finally getting out of the house about 15 minutes later. There was not much sleeping at their place after that. Thank goodness I kept the dog at our house Friday because the opossum has been in their house since then, and it would have scared the crud out of me. I think I would have called the cops to see if they could come get it. Also thank goodness it didn't come out while they were awake or decide to sleep in their room. Anyway....at least it is over and everyone is fine. Also, thank goodness they didn't put poor Leo down. He is still going to have his check up, but we're thinking he probably isn't crazy.