Parker has been walking on his leash well since I got him at 10 weeks. Last week he was fine, then went whacko- looked like an alligator doing a death roll. He wasn’t acting funny before he stop/drop/rolled. It was so intense I feared he would break his neck. I tried to restrain him and his martingale buckle popped open. Fortunately I was able to scoop him up and rebuckle it but I had visions of never seeing him again. New martingale arrived 2 days later thanks to Amazon Prime. No buckle. I get him used to the feeling of this new collar in his yard and at his puppy class and he’s fine. Sunday we go for our walk down my 1/4 mile driveway. Get halfway and he death rolls very violently out of the blue. He’s not acting afraid, there’s nothing to scare him. I physically restrain him because injury seems likely. Carry him home. He’s worse yesterday. So today I try his safety car harness that fits very well. He’s walking very relaxed, no pulling and then death roll. He gets his leg free, gets the harness stuck in his mouth, I’ve got a firm hold on him telling him “Stop! Shhh!” He lets me fix his harness and I carry him home. He’s calm the whole way. My knees are shaking so badly I can barely walk.
I’m at a loss for how to proceed.
I’m at a loss for how to proceed.

