I wish my dog was dead.
Why would you say that about your dog?
I wish I had one of those angel dogs
That is a terrible thought. People would give anything to have their pets with them and you just want yours to die. It's not okay to want someone or an animal to die for any reason.
On second thought, I don't want them to die. But I still want an angel dog.
Then you should enjoy your time with them, it's very precious. Why not buy an angel costume for it? It's cute.