Strange behavior in cat.

Hello.

My cat got hit by a car four months ago and had to have his tail amputated a couple weeks after that due to nerve and vascular damage. He broke no bones. They of course shaved his tail and surrounding area around for the surgery.

It is now several months later and as of a couple weeks ago he has had two "incidents," possibly seizures. The first one lasted about 30 minutes. He was sleeping and then woke up and started running around like a mad cat. His fur was fluffed up like he was scared, and the skin on his lower back and tail were twitching almost uncontrollably. He kept either running or twisting around to lick and bite the fur at the base of his tail (nub). He would pause and stare at me with his head held crooked and pupils very dilated, and then resume. It looked like he was looking at me but through me. Finally he laid down and peed on himself, which he has never done. I cleaned him up but he just continued lying there for about an hour. Afterwards he seemed fine.

I thought maybe he had just had a bad dream, but a similar incident happened at 4 this morning. This time it lasted longer, but did not seem as severe. He did not pee on himself or have his fur fluffed up. Unlike last time, his ears as well as skin were twitching. It lasted about 45 minutes before he fell asleep. Over the next few hours he would occasionally wake up and his fur would start twitching, but it wasn't as severe.

He does not have fleas. He did not meow during these instances. His fur appears mostly grown back from when they shaved it, but perhaps it is itching him. I also thought maybe the nerves were still regrowing and causing strange sensations back there, or he is having some kind of flashbacks.

Thank you!