My 6 year old rabbit has chronic rhinitis as well as relatively advanced dental disease. To prevent/manage his condition, he gets Penicillin G injections every 3 days. He has been on this regimen for a few months now. His behavior has been better, his eating, pooping, etc. is normal, if not better. Today, I gave him his injection, and as I was rubbing the injection site after removing the needle, he flopped completely over, almost as if he dropped dead. He could not move, but he was breathing seemingly normally. I immediately put him in a crate and rushed to the vet. Within minutes of being in the crate, he began to regain movement and got himself sternal and seemingly back to normal. The vet could find nothing unusual, other than his tongue being a little more on the purple side of pink, but not super abnormal. Because of his sinus issues, she thought perhaps he had been stressed and might have just had a lack of oxygen and blacked out for a moment. He is typically not stressed very stressed during the injections, and never struggles, or scrambles when I pick him up or give the injection. He did flinch slightly when I injected him today, which I thought was a little odd. When he flipped over, I thought I might have touched his spine by accident, but the vet thought it was highly unlikely. She suggested that he also may have had a seizure. Has anyone ever had a remotely similar experience? I am so happy that he seems to be okay now, but I would love to know more about what might be going on. Thank you for any and all help.