I've spoken to my cousins Bella and Bristol about this and they both agree with me, so I've come to the conclusion that every inside-dog in the world has the problem of vanishing toys. This is obviously because all you humans have the most inconvenient furniture!
At our place my toys are constantly vanishing in between couch cushions or rolling under items of furniture, which really is the fastest way to ruin a decent play! Sometimes they vanish so quickly that I wrack my brain trying to figure out where they've gone and search for them high and low. Other times I can actually see my toys about to vanish and try to prevent it, by running after them and growling, especially if they're heading for under-the-couch!
Under-the-couch may as well be called 'in the abyss' because it takes mommy ages to get toys back out from under here! It's not as if she doesn't know they're under there: I always let her know by leading her towards the couch and growling in its direction. Then I make it really easy for her by sitting in front of the exact spot that the toy rolled into and wait patiently for her to retrieve it. Even despite me doing all this, she takes way too long and this is another thing that makes me grumpy! I mean, I'd get it myself if I had longer limbs, it's not like it's hard! Right dogs? Who's with me!