Off doing something brave, alone, at full speed.
Often a Jack Russell Terrier, Whippet or Siamese, though every pet is its own animal.
The Stunt Double is off doing something brave, alone, at full speed. Not unfriendly, just busy. There is a wall to be jumped or a thing to be chased, and it is not going to jump or chase itself.
A dot on the horizon, coming back eventually.
Uses the furniture as terrain.
Happy to run alongside; not much for standing around.