Well, we had one of those moments this afternoon. I went to meet friends for lunch, and gave a pat to all three critters in turn before leaving. Fast-forward a few hours; when I came home, I saw Captain (kitty) and Mini (Chihuahua), but no Stanley. Mark hadn't seen Stanley either. My cats are both indoor-only cats, so even though Stanley has a name tag, I started worrying about whether he'd sneaked out of the house. I looked all over the house for him. Upstairs, in the basement, on the first floor. Behind all the furniture. I called him repeatedly. No dice.
Then it dawned on me to look IN the sofa. We have a couch and a love seat, both of which have recliners at both ends. Therefore, we can't look UNDER the couch visually, as the bottom of the recliners reach nearly all the way to the floor. But it's possible to look under the sofa in a TACTILE manner by sticking an arm down the narrow gap between the seats, where the backs of adjacent seats meet adjacent seat cushions,
I inserted my arm down into said gap. And felt one surprised little cat, who gave me a "Prrr!" and started sniffing my hand.
"Stanley, you hairy cat! What are you doing in there? You worried your Meowmy half to death."
Good thing he's cute. :-)