My dog is basically a dragon, who instead of hoarding gold, hoards Kongs. On weekdays, we like to leave him a Kong when we leave, gives him something to do for a while. As new dog owners, we bought 2 of them (so one could always be prepped in the freezer) and one day we noticed we were down to 1, and then down to zero.

We have a small house and a small backyard, so surely we can find them. But no, they are gone. So, we bought a third Kong. Gave it to him before work, come home from work and all 3 Kongs are now in the living room. We had 3 Kongs for a while, until slowly they disappeared, one at a time until we have no Kongs.

So... the fourth Kong was purchased. We give it to him before work, and come back to all 4 Kongs piled in the living room.

The Kongs are dirty, and he's a lab, so we're pretty sure he's burying them somewhere while we're gone, but in our tiny backyard, we just can't find a dug up area. So apparently, not only is he burying his Kongs, he's also smoothing the mulch back out over top of the hole so we can't find them.