What is that behind the tree?

On Friday afternoon, I was sitting in my chair out on the deck and I saw something funny behind the tree. At first, I thought I was seeing things but then I saw it again. I just couldn’t figure it out. I thought I was going crazy for a moment, until my husband came out and said the same thing, that something looked funny about the tree.
As we were brainstorming about what it could be, we heard the horses neighing at what looked like the same tree we were. We didn’t think of what it could as we went back inside to have dinner. I was getting out the steak and potatoes. After my husband got the grill lit, he yelled for the steaks that had bee tenderized and ready to go. As he got the steaks on the grill, our daughter came home from school, as I was about to peal the potatoes to put them in the oven. She said “Hey Mom!” and went on upstairs to do her homework and get ready for dinner. About thirty minutes later, dinner was ready and I called to her to come downstairs to eat. When she got down stairs, she set the table and got the glasses. He brought the steaks inside, put them on the table, and I got out the potatoes. We all sat and had a wonderful delicious dinner. After we had finished and were washing the dishes our daughter said that something was behind the tree. It was the same tree we were looking at earlier. She started screaming in excitement that she figured it out. She said one of the horses got out and was behind the tree and the other horses were neighing at him to come back.