Different from a frisbee in that it goes further and more accurately. It is more rigid than a frisbee but is more prone to go off-line when damaged. It's also more expensive but dogs love them. Careful that you don't injure the dog by throwing it too hard too close - they can hurt.

Hi Jerry

I have seen something that looks like a hoop (or a hollow frisbee) and is quite light and almost has a boomerang-type effect. If that is an aerobie, I can imagine it being a lot of fun with a dog attached!

That's probably an aerobie then Snoopy. A circular one should fly straight and true. You can get one that will come back, like a boomerang, but it's triangular. If the aerobie gets caught in the wind it can come back to you and if it is not thrown flat it will bend in flight.