DC Comics has struck a deal with General Mills to include slightly-smaller-than-standard-sized Justice League comic books in with various creals like Trix, Cinnamon Toast Crunch, Lucky Charms, Honey Nut Cheerios, Golden Grahams and the like.
You'll note that all the characters are in their old-school costumes and not the New 52 'new reader grabbing' looks. Silly Superman, red underpants are for kids!
24 pages with no ads at a 5×7 inch size, the stories in each of these four books will be continued on a microsite they've created called bigcerealheroes.com.
Here are the covers for the 4 different issues, which should be showing up in cereal boxes around Halloween time.