my dog is nearly three and for the last 2 years he has had a toy, a small rubber simba lion king toy, every night with out fail, he carries it in his mouth and runs back and forth from one end of the house to the other and he cries and looks very distressed. he never plays aggresively with the toy like he does with others, but a few times i have caught him rolling the toy onto its back and cleaning the toys stomach whilst still crying. i always wonder what he might be thinking and why he is acting this way. why does he do this?