Thank you for your post! This has been happening to Horse since he was about a year old (he's 4), approx 2-3 times a year. This first time it happened was so scary! I just sat with him and talked to him, (through my tears!), and he seemed completely fine after. It didnt happen again for almost a year, thinking he was having a seizure, I called the vet. They had no answers for me, other that to put him on anti-seizure meds, which I didnt do because these "head bobbing episodes" didnt seem to affect him at all and happened very infrequently. We've since switched vets, because I didnt feel that our previous vet had enough knowlege of this breed. I feel so much better knowing that this head bobbing is somewhat common in bulldogs and that it doesnt harm them. I actually woke up to it happening Horse this morning...and told myself that I would find more information about it today! Your post was perfect timing!