This morning Lexi was on my bed with a greenies while I was getting ready for work. After I got ready I had to take her out one more time. I grapped her leash and went to put it on her. As I was trying to put it on she let out this really mean growl and bared her teeth at me. Like she was going to attack me. She has NEVER done this before. Well maybe when playing but this time she meant it. I took the greenies away and put Lexi on her back and while staring her in the eyes I told her NO!. After awhile she looked away and I let her go. She did it again when I went to put her collar on. So I did the back thing again. I have no idea why she would do this. I think she might have been testing me because afterwards she was fine and was licking me when I took her out. At lunch she was back to herself.