I have one of those feather toys on a long stick. If you move it around fast enough, it sounds like feathers flapping. All the girls go nuts for it, as they run and jump around trying to get this fast moving "bird". When my youngest catches the "bird" she pulls till I let go of the stick, runs around the house with feather in mouth and stick dragging on the ground behind her, she does a full lap or two around the house before coming back to me and dropping the feather in front of me. What in the world is my little cat doing? Is she doing like victory lap, what purpose does it even serve? It's funny and I love it, I'm just curious why she does it.
That is how cats hunt in the wild.
While hunting small animals like mice only requires a well timed paw strike, cats employ different tactics for slightly larger animals. They usually bite the neck. Later, if they can, they pinpoint the prey and if they can't, they drag the prey until it can't resist.
Victory dance also fits to general cat behaviour. Many cat owners woke up to their cat bringing presents. I had a cat who waited by his kill every time until someone takes the poor animal to a trash can. He really was proud of his kill.
So, I would say it is not nuts, it is a healthy way for a cat to engage in game play. I'd also say he is quite lucky to have an owner who plays regularly.
I hope this helps.