I have a miniature dachshund who will only play with toys at night, once everyone is asleep. When every light and television in the house is off, he makes his way down off the bed, eats any leftover food he's not consumed during the day, and plays with toys.
We know this because we've caught him, and we occasionally wake up to what we refer to as "crop circles"; he arranges his toys all around the room. The dog does not play with the toys when prompted to or enticed to do so during the day, and he doesn't fetch or actively play when we can see him (though when he does break character, we love it and praise him). It is only at night that he seems he's the happiest.
Of note, it's this same guy; this is what he gets up to when he's not decorating the throw rugs yellow.
What is his deal?