Pokémon cards have evolved from childhood collectibles into serious assets. And thieves are trying to catch ’em all.

Sales of collectible trading cards like Pokémon and sports sets are surging, with Target reporting a 70% year-to-date increase and expecting over $1 billion in annual revenue from the category.

Pokémon cards are having a resurgence — and it can be an expensive hobby. Many parents need a crash course.