We live in a fairly rural location. Fields all around the house so at night, outside of the light of the outside light, there's just darkness (this is important)
Put puppy (8month Golden) to bed at around 12.30 (he'd been asleep on the bed with us till then but he gets moved to the kitchen for proper bedtime)
At 2.30am he starts barking and barking and they were proper growly barks. He's NEVER done this before, I got up after a little while (because he wasn't stopping) to check on him and DH said I should do a lap of the house outside to make sure everything was ok!! Needless to say that didn't happen.
He seemed fine when I got up and was quite all night after that but it did freak me out a bit wondering if there was someone around.