Marshmallow-only Lucky Charms boxes are a real thing -- but there's a catch

Boxes of Marshmallow-only Lucky Charms are apparently a real thing -- but there's a catch.

There are only 10 boxes.

"The Lucky Charms team receives countless calls, emails, tweets and Facebook posts from marshmallow-obsessed fans longing for a box filled with only the magically-delicious marshmallows," General Mills posted on its official blog.

So how can you get your hands on one of the 10 boxes? Share a "Lucky Charms Lucky Selfie."

"It’s simple! Just share a photo of yourself holding an imaginary box of Lucky Charms on Facebook, Twitter or Instagram between October 14 and 18 using #Lucky10Sweepstakes," the company said.

The sweepstakes ends on October 18.