What is this Mike's Hard Lemonade black bottle top thing?

Question

My parents just bought some Mike's Hard Lemonade and in it came a black bottle top. It's made of plastic, and it is the neck and cap of a Mike's Hard Lemonade bottle. The bottom of it is open and when you push down on the inside, it clicks like a stapler or like a pen. When I look closely, I see a little spring. My dad and I can't figure out what it is! The cap doesn't come off; it's sealed on. Does anyone know what it is?

Answer 1

it's an idiot proof cap.

Answer 2

Childproofing more than likely...

Answer 3

take a picture of it so i can see what it looks like. try pushing down and twisting it?