Strange Sleeping Habits/Episodes?

Hey there, obviously I'm going to take the poor dear to the vet, but I was wondering if anyone had experience with something similar?

My cat (about 10 years old) is slightly overweight but otherwise healthy. She's playful, eats well, drinks well, has normal bathroom habits.

However, when she sleeps, she seems to go into strange episodes.

I know it's reasonably normal for cats' faces and paws to twitch when they're sleeping, but she tends to tremor all over, with her whole leg jerking, face contorting, etc. At least twice I've been unable to stop her from falling from whatever perch she's slept on (and she seems to only wake up when she hits the ground).

Curiously, I touched her head during one of these episodes, and she jerked away and growled- but did not visibly "wake up". I also noticed that her ears twitched in response to noise I was making.

Could this be considered a seizure? Has anyone had this experience before?

I really don't know whether these are really full-on dreams or if there is more to it.  But I do know that humans can lash out if disturbed during a dream, so there is no reason that a cat wouldn't react similarly.  I'm only guessing, but the fact that she growled when disturbed would sound more like full-on dreaming than a seizure, when she would be unlikely to respond to outside stimuli.

Is this a new thing?

I hope someone here can be more helpful.

And welcome to TCS!

I have seen Silly do that.  I assumed she was just having a vivid dream.