To answer your question about what a dog seizure is like....There are different types, but this is what I've seen with one of my dogs..
Molly, who was with me from 1995 - 2003 had seizures that would last 2-3 minutes (seemed like an hour). I could tell when one was coming on b/c she would start circling around, almost like she was chasing her tail, then she would just fall over and start shaking violently, foamed at the mouth, and didn't respond to anything. Although she would shake like crazy, every muscle in her body would be tense. All I could do was just try to comfort her, although I don't think she even knew I was there. I'd think this is the worst kind of seizure, but I'm not sure. Hope this doesn't scare you, but the seizures she had was caused by cancer in her brain. It wasn't epilepsy. She had cancer on her spleen about 8 months before (that tumor was the size of a baseball), had her spleen removed, but it wasn't caught in time, the cancer spread to her brain. Just remember, these were violent seizures that she had and they started out of the blue when she was 8.....The vet at first said to keep an eye on her, and if she has 2 seizures within 24 hours to bring her in. Well, she had 2 seizures within 4 hours.....