What the weird?? How does that happen?

Blake is day-time potty trained, but still has to sleep with a Pull Up on at night. But lately, he's been soaking through the Pull Up a LOT, which means I have to change the sheets a LOT. Well, this morning, he woke up and his pajamas were soaking wet. I told him to go strip it down in the bathroom and throw his Pull Up in the trash. Well, he hands me his Pull Up and it's completely DRY!!!! HUH??!? How does that work?? His little willy must have been hangin' outside the Pull Up or something! So bizarre.....