A ponytail is a noun, used to describe the hairstyle in the video. All the hair is tied back and looks like the "tail" of a "pony."
There are several ways we can say this:
"put my hair in a ponytail" | "tie my hair in a ponytail" | "create a ponytail" | "make a ponytail"
What do you think of the father's invention? clever or not?