My son did this. When he was about 2, I had his crib next to mine for a bit. I woke up one night because there was something wet on my pillow. After I was fully awake, I turned on the lights to find out that precious son had taken off his pj's and diaper, ripped through it the diaper, and thrown the wet gel all over the room. Nasty! He did grow out of it, but for a while, I had to safety pin the zipper to his sleepers up so he could not get to his diaper.