Dog becoming toy aggressive?

Then correct this poor behavior immediately and/or seek professional help for yourself on how to train a dog properly before it gets worse (and it will) it injures someone, you're sued and the innocent dog is euthanized.

If this is going on, resource guarding, remove them. And if you are trying to get the toy away - trade. Make what you have more appealing to your dog. But this behaviour does need to be corrected. And instead of backing the dog into a wall, so to speak, prevent/avoid the situations that produce this kind of reaction. And train the dog to 'drop' or 'leave. It might save his life one day.