Why does my toddler turn into a nocturnal parkour expert the moment lights go out?

I am currently writing this from the floor of my son’s nursery, watching him attempt to scale his crib like he’s training for the Olympics. We are deep in a sleep regression that feels more like a tactical siege than a developmental phase. My partner and I have tried the gentle sleep training methods, the blackout curtains that cost more than my first car, and enough white noise to simulate a small thunderstorm, yet he remains a tiny, energized agent of chaos. I’m starting to wonder if his circadian rhythm is just calibrated to a different time zone entirely—perhaps one where sleep is strictly optional. Has anyone else experienced this sudden shift from a perfect sleeper to a midnight acrobat? I am genuinely curious if there’s a biological reason for this defiance or if I’m just witnessing the first signs of a very stubborn personality. How do you maintain your own sanity and sleep health when your little one treats bedtime like a late-night rave? Any advice or solidarity would be greatly appreciated while I sip my lukewarm coffee.