.........
So today as i woke up i heard barking from my backyard and I realized it wasn't my dogs barking,So i went to go check and there was another dog in my yard with my other 2 dogs i was really confused and it was just barking and running around in circles,but when i open to door it comes running and starts licking my fingers and stuff ,but when i close the door it starts to cry ,but Ive never seen it in my entire life.
What to do.....
Edit:
got new pic:

My cousin gave it the green collar.
It's Female.