Dog Seizures

So my dog Charlie had a random seizure out of nowhere yesterday. My mom had just fed him lunch and all of the sudden his body started shaking and he couldn't stand up on his legs as they slid out from underneath him. I though he was choking on something and therefore tried to open his mouth,but it was locked tight. I was pretty sure he was dieing. After like thirty seconds he got up and was totally fine. We took him to the vet and they said that it isn't uncommon for some dogs to just have random seizures every once in awhile. Crazy huh?