My first muzzle loader deer I shot,(with .54 hawken), did very similar to what you said.
Scarilly so.
It was a doe,50yds, and she fell towards me down a bank, and thrashed around.
I feebly tried to reload as fast as I could ( I had practiced on the ground *&#@!. Big differene in a tree!)
She fumbled around, as I was doing, and suddenly...she just stood up.
I tried to hurry, but she started walking off. I couldn't believe it.
As I packed down the bullet, I just threw my loading rod away, as I tried to put on a cap, and throw the gun up.
She just walked up over the bank, and was gone.
I climbed down, grabbed my loading rod, and saw lots of blood.
I couldn't believe she was alive.
I walked over the bank where I had shot her, SURPRISE, she was lying about 10feet over the bank ALIVE, and she sprang up and became "superdeer" as you said.
I didn't have a shot.
I couldn't believe I had pushed her so blatantly. This wasn't my first hunt, or kill. I KNEW what to do.
I was so caught up with the blood, and how vioently she acted, that I just couldn't
believe she was that alive.
We found her later that day, about 200 yards from where she sprang up.
The bullet had hit her high and slightly back in the shoulder, but under the spine, and went straight through.
I guess the shock "stunned" her nervous system, and caused her to spaz out.
As others have said.
Lesson learned.