Thomas took off his own diaper!

Thomas had taken off his own diaper last night while sleeping. Around 1 a.m., he woke up crying, and I got up and found one side of his diaper off. All the blankets in his crib was wet! I flipped over his mattress, changed the crib sheets, hand-washed his pillow, and washed him. I couldn't believe that he could take off his own diaper! I hope this isn't something he'll be doing often!