Yesterday during the 2nd race of the day, Missy was chased by a large pit mix. The first heat of the race went fine, but while getting ready for the second, I looked over and there was a dog that I didn't notice before. He was very fixated on Missy and she had her head turned barking in his direction. I don't think she was actually barking at him, but it's possible. So used my hand as a blinder and to point her face forward so she wouldn't antigonize the dog any more. Well, when I let her go, she got about halfway down the lane when the dog got loose and was following her toward the box. I'm not sure if he was supposed to be let go to run, or if he managed to get away from his owner. We weren't ever able to confirm. Chaos ensued as his owner and other people tried to stop him, and of course the judge blew his whistle. He met Missy at the box as she turned, and I could see the terror in her face as she realized this dog was chasing her back down the lane. She hates being chased, especially by dogs 2-3x's her size. I ended up barely catching her and picking her up and the owners caught their dog. I turned around and looked at Mike, and he just nodded his head like, "she's ok" and came over to ask me if the dog got Missy in the shoulder. I don't think he actually touched her. The main reason I picked her up was because if the dog caught up to her, she was likely to turn and snap at him, and I didn't want the situation to escalate any further and potentially get her excused for agression. Mike told me to re-run her to see what she would do. When dogs cross over lanes, the judge will let the dog who was chased run the pattern by themselves if the owner wants them to. When something goes wrong, it helps if they get a chance to successfully run the pattern. I actually just wanted to see if Missy would still do it. Unfortunately, as I suspected, she was very hesitant about going down the lane. When I first let her go, she went about 5 feet then turned around. My friend Dee, who was taking times outside the ring, yelled to run with her. So I ran forward with her and that got her going down the lane about half speed, but instead of getting her ball, she just quickly triggered the box and ran back without it. We set up to run the last heat of the race and Missy wasn't herself. She wasn't barking, wasn't pulling forward like she usually does. It was very obvious to me she was concerned. Sure enough, she went down the lane and just triggered the box without getting her ball. When I re-ran her she did it again. Our box loader said she wasn't even looking at the ball, and instead was looking around for another surprise dog. As I walked out of the ring, I was fighting back tears. My thoughts went to the worst possible scenario, that Missy was going to have to be pulled from the rest of the tournament (only 2 races left). Then we would have to work at practice to get rid of her fear of the box, which really she was afraid of a dog coming out of nowhere while she was at the box. I was worried my little girl was "broken". Mike tried to comfort me and said we would work on box work during warm-up in the next race. I decided to grab our frisbee and take Missy outside to play to get her mind off of it. She was still a little worried. Playing frisbee helped, and luckily she was back-up on another team. I was able to take her into the ring during their warm up and work with her. At first she was a little apprehensive, but she finally got into it and started getting her ball from the box. By the time our next race came up, she was back to normal, barking, pulling, determined girl. We were able to successfully finish up the weekend. The dog that chased her was excused from the rest of the tournament for not being ready to be in the ring. The judge at the time was from the same club and agreed that the dog shouldn't have been in the ring yet, wasn't experienced enough. My friend Roberta, who also has a Sheltie, is also on that club and was in the ring when it happened. This was the same dog that she had told me about earlier. He scared her Sheltie in practice on Friday. She was really upset about it. After I cooled off, I talked to her and I tried to make light of the situation. It wasn't very long ago that Missy had her own chasing issues. She has never been excused and never had the same effect on the "chasee". Probably because she's smaller and less intimidating. So I told Roberta that Missy had just gotten a taste of her own medicine and she didn't like it. Also, as we were leaving the ring right after the incident, Mike said to me, "we need that dog at practice when Missy is running around" because Missy is naughty at practice every once in a while an likes to run around and bark. I didn't laugh at the joke initially because I was so upset, but after I cooled off it was funny. Roberta relayed what I had said to the owner of the dog to make her feel better. The owner felt awful about what happened. I would too. I don't think the dog was being agressive, he was just excited and wanted to chase. A lot of dogs do that when they are just learning. They see the motion of the other dogs running and their brains just go haywire and they forget what they were supposed to do! The problem is he is BIG and that's kinda scary for a 25lb Sheltie.. and me. No hard feelings from me. Nobody got hurt, I was just worried for a bit that my dog wasn't going to do flyball again. But that is not the case. I have a very confident girl and she was able to move past it.