I experienced sleep paralysis couple years ago while traveling in a van. We were coming back to South Finland from a skiing center in the North, where we spent the Labours day holiday partying hard. I was having such a horrible hangover and sleep deprivation, so I tried to get some sleep in the car but ended up only dozing and having this "seizure".
It made me panic, since I didn't understand what was happening, but thought that I was all of a sudden permanently paralysed without doing anything. I remember that I tried to yell "I can't breath, I can't breath" while being unable to move my legs or turn. And it felt like it lasted several minutes, although it didn't probably take more than 10-20 seconds. I was so relieved when it stopped, but also too afraid to tell any of my friends what happened before googling if that was some serious symptom of something. Anyway, I think it had something to do with drinking too much and not sleeping enough.