A souvenir was like...something unique that immediately remind you of that place.

Big brother's gonna return from another world tomorrow; I wonder what kind of souvenirs he'd bring us?

...

Tomorrow finally came.

A portal opened in the dining room.

...and big brother's rotting corpse fell atop our dining table; trampling all over the food.

Since it'd be a waste anyway, let's just eat big brother, shall we?