I've found these Wonder Balls a few times. They are kind of like a Kinder Egg but there is cany inside the chocolate balls and the prize just sits in the box.

Here are a few close up shots of the box

here is the ball in the foil and two bonus stickers also in the box.

There are 3 prizes that I've managed to get in 3 balls.

If I manage to get another one I'll take pictures of the candies and hopefully the unwrapped ball.