Spike the Bulldog

Spike The Bulldog is often seen as a minor antagonist in Tom and Jerry, though he is also a protector of sorts towards Jerry Mouse - however there is no denying that Spike is often unjustly cruel towards Tom (a stereotype of dog/cat rivalry) and although he often gives Tom several chances to avoid his wrath he will attack the cat viciously once those chances have been spent.

Tom often tries to get revenge on Spike, so it can be argued that much like Jerry Mouse himself Spike can play both the good guy and the bad guy depending on the cartoon - in general though he is a bully in regards to Tom and threatens bodily harm to the cat, to the point of making Tom fear for his live on numerous occassions.

Spike can also be friendly when he wants to be and is seen to be a caring father, showing that although a fierce opponent he isn't entirely without merit.