Given: a large network that operates worldwide through franchises and its own stores.

Goal: create viral content, make people look for your store in any trip and go inside.

Solution: Lego releases its own passports and gives each store in the network a unique stamp. The passport is given for free - you just need to ask the seller. Inside, you can make your own portrait using stickers, and then run around stores collecting stamps.

The network does not disclose metrics, but I can highlight a number of advantages:

low cost of the passport and stamps. In mass production, the passport will cost no more than 50-70 rubles;
High margin on all products will cover the passport even if you buy a Lego keychain at the checkout;
Most people will not leave the store empty-handed. Every single one;
People love collecting and will run to every store on a new trip;
The passport is a great news hook. For 100 passports, users likely generate at least 100 pieces of content; immediately I think of 4 per person: got the passport; got the first stamps; got an unusual stamp; filled the passport;
An additional reason to open a Lego franchise rather than just a construction toy store, as the brand creates traffic flow.

In summary: we have a very cheap product to produce that itself generates sales and a ton of viral content from users.

P.s. I also wanted such a passport for myself.