If possible the next time it happens see if you can record it - on your phone if nothing else. Then let the vet see what is happening when it happens. What you are describing could be seizures but the only one who could tell you for sure is the vet. Just keep an eye on him and treat him the same as normal.
Assumptions do nothing but make an ass out of u and me.
We can stick our heads in the sand for only so long before it starts choking us. Face it folks. The pet population is bad ALL OVER THE WORLD!