The Pokemon Company and McDonald's have teamed up before, but not without attracting undo attention from would-be scalpers. Earlier this month, McDonald's Japan was forced to end its latest Pokemon Happy Meal promotion a few days early because the supply of cards quickly ran out amid chaotic crowds clamoring for the cards that came with them.

TOKYO (AP) — Fast-food chain McDonald’s Japan has canceled a Happy Meal campaign that came with coveted Pokemon cards, apologizing after resellers rushed to buy the meals and then discarded the food, leaving trash outside stores.

McDonald’s latest Pokémon-themed Happy Meals promised a playful mix of nostalgia and excitement. Instead, the launch sparked an unexpected frenzy that swept across Japan, leaving restaurants overwhelmed and the promotion cut short.

Piles of untouched Happy Meals littered sidewalks outside McDonald’s restaurants in Japan as frenzied customers scrambled to buy limited-edition sets with Pokémon cards over the weekend.

The ‘little monsters’ cards are extremely popular among both children and adult superfan collectors, with some going as high as millions of dollars in value.

Fans swamped the restaurants to collect the cards, with some discarding bags of food after buying, and police called in to mediate disputes.