It almost writes itself, doesn’t it? General Mills’ Lucky Charms cereal has always been known for its green-clad mascot, a mischievous fellow who is always determined to keep the “magically delicious” cereal of pink hearts, yellow stars, purple horseshoes, green clovers, blue moons, red balloons, unicorns, and rainbows away from whichever meddling animated brats are hoping to get enough sugar for breakfast to power a medium-sized city. So why wouldn’t another green-clad mischief maker, whose name just so happens to line up almost exactly with the beloved breakfast cereal be able to slip right into his place and get some delicious, Saturday-morning breakfast for himself, right?

That’s where Loki Charms becomes a reality.

General Mills will produce a limited supply of 3,500 boxes of Loki Charms cereal, and they’ll be available exclusively on MischievouslyDelicious.com for $8 a box (including shipping) beginning at 11 am Edt on June 9. Hey,...