Worlds-within-worlds stuff is always complicated to explain, but here we go… Readers of the Invincible comic book (from Image Comics) will recall that perhaps the favorite comic book character of Mark Grayson (aka Invincible) is named Science Dog — pulp hero of comic books, Saturday morning cartoon shows, and numerous product tie-ins. Well, the creators of Invincible eventually started putting actual Science Dog stories in the Invincible comics as back-ups. Now, Image Comics has collected the original full-color Science Dog stories from Invincible #25, #50, and #75 in Science Dog Special #1, coming this September from writer Robert Kirkman and illustrator Cory Walker. Science Dog! Once an ordinary pet dog living in a brilliant scientist’s lab… but then transformed by a freakish time-travel accident into a super-smart, super-strong humanoid adventurer on a never-ending mission to destroy evil! Got all that? You can find out more about the story at ComicVine.com.