Cat seizure

[CrazyLucky]

I came home from the long weekend and my 14 year old cat seemed noticeably skinnier.  Then, while we were unpacking, he started convulsing for about a minute.  He can barely move, he has no strength and he just lays with his head next to the water bowl. He also vomited, but it's clear. It doesn't look like he ate anything. My other cat seems normal. I'm taking the sick one to the vet tomorrow. Google says it could be a lot of things. Does anyone have a similar experience you can share?