I have to add to my post earlier......... the cat - almost as big as the 25 pound rat terrier - is poly dactyl - is a beast of a cat - just big boned and solid. Anyway, the cat will wait for the dog to come by and then swat at him and run. Of course, the dog chases him and the cat runs to my wife and meows like "Help me!". My wife always scolds the dog. I have told her countless times... UM, the cat picked that and tricked you. I am not sure she believes me. I have to record that one of these days.
The other bizarre thing my dog does..... will chase a tennis ball inside the house and play fetch etc. just like a normal dog. Go outside, throw a ball, he will look at you like you are dumb. BUT, go outside and throw a snowball down the driveway or throw them in the yard... he will chase them, bring them back and eventually eat them for hours. You have to end the game before he gets too cold cause he will eat snow to the point he is shivering..... and he still wants to play. ( We live in NE ohio so there is plenty of snow) - I have gotten to the point of freezing snowballs at the end of the winter and throwing them for him randomly when it is not remotely winter time just because he has such a blast chasing them bringing them back, eating part of it and begging you to throw it again!