This bottle. Our girl ripped out the rope almost immediately. We put a tennis ball in the bottle and now a few tiny treats provide her hours of entertainment.

We got this one for our golden during that time. I filled it with treats, set it on the ground..

and watched him flip the entire thing over so that all of the puzzle pieces fell out and he got the delicious treats.

My advice? get a busy buddy (just watch your shins, when they start swinging it it's like a mace). My boy loves it.

I've thought about getting one of these, but I haven't been able to see one in person to tell if he'd knock it over or not.