Yes, I'm an idiot. My boa either leaned and crawled along his sliding door and moved it or managed to get his nose into a crack and slide it open. Either way he's out. I've looked everywhere (behind everything, behind/under/inside all furniture, behind/under/inside all the appliances, no luck. Any favorite spots I might not have thought of? I'm down south so it's warm enough in the house that he won't be needing to find warm spots like near electronics and that sort of thing. I don't think there's any gaps where he could have escaped outside but I know they sometimes surprise us. I once lost a baby Cali kingsnake for 6 months before it turned up out of the blue (no idea what she ate but she hadn't really grown) so I haven't given up, but I'm pretty discouraged. It's been 4 days.