We Found A Guinea Pig...?

I've never personally have this happen to me but I guess that since u have a hamster ur comfortable with rodents so I say u pick it up and put it in the bath tub cuz the sides r slick and it can't climb out and then wait for the owners and go tlk to them and ask if u can have him if ur grandma will let u and take good care of him and feed him and tlk to him and play with him a little and get to know his personality until the owners come home