Dog had a seizure last night

[Duck Butter]

My dog had a seizure last night. He is terrified of thunder and will try and get as close to you as possible. He jumped up in the bed last night shivering as usual when it thunders but then started having a seizure. Went on for about a minute than ten minutes later had another. I watched him the rest of the night and he was fine after that. He would try and stand up and lose his balance and then his whole body would shake, then his muscles would almost lock up. He is going to the vet this afternoon. Anyone ever seen this before with a dog? I don't know if was something he ate or what