Nintendo has been caught off-guard by the success of its Amiibo line. While it hoped there would be demand for its expansion into the toys-to-life space, the company's "expectations have been smashed."

That's according to Nintendo UK consumer marketing boss James Honeywell, who told MCV, "Right from the outset we hoped that Amiibo would be strong, but even our expectations have been smashed. With a unique lineup of iconic characters that are loved by so many people, it really has been unprecedented."

Companies like Activision and Disney have also enjoyed success with their respective toys-to-life offerings, Skylanders and Disney Infinity. There was some question of whether the market would be too crowded for Nintendo to make an impact when it launched Amiibo alongside Super Smash Bros. last year; instead, with 5.7 million sold as of February, its primary problem has been keeping less-common figures in stock.

"We hope to do a better job of satisfying these needs in the future with more stock, and, while there are always going to be some times when we can’t on certain characters, I suspect that is also part of the appeal," Honeywell continued.

Indeed, tracking down and collecting rare figures has become a game for some, but for many others, it's proven to be an exercise in frustration.

Honeywell cites collectors' desire to get their hands on every Amiibo available as part of the reason for the supply issues. Nintendo has previously said it won't be able to consistently keep every figure in stock, though it will deliver additional runs of certain figures in select circumstances--something we saw with Marth, for instance.

In addition to sitting on your shelf, Amiibo serve a purpose in various games, including Super Smash Bros., Mario Kart 8, and Code Name: Steam. For a complete list of every Amiibo announced to date (along with their in-game functionality), check out our comprehensive list.