A new flavor of Poop Cola, Dark Poop, has been unleashed upon the city, and Dib needs to find a bottle after accidentally spilling Gaz's. His search almost comes up empty, but he finds one last bottle at a mysterious convenience store. There, he is witness to a pair of battling wizards using Poop Cola to fuel their magic.
So, obviously this is a ridiculous premise. That's nothing new for Invader Zim. In fact, that's its bread and butter. The setup is funny too, with Dib enraging his ever-terrifying sister once more and being forced to appease Gaz, lest he face her terrible wrath. It even has Dib self-narrating in his head, as if he were in noir fiction.
Where the story falls apart is in its constant reminder of how ridiculous the premise is. It doesn't have a lot in the humor department outside of Dib constantly talking about how absurd two wizards using Poop Cola to battle is. I mean, it is absurd, but you must put a little more in the tank than that.
There's another scene of Dib rattling off all the different flavors of Poop Cola there are; it's alright. There are a couple of good poop jokes in there like "Solid Poop" and "Poop Water."
Beyond that, it comes off like a lesser issue of Deadpool; it has no jokes but making fun of its own bad joke.
Even the art seems a little off this issue. Maddie C. predominantly still recaptures the look and motion of Jhonen Vasquez's original Invader Zim, but it's a little too fluid at times here. The characters shift too much in motion, and the Poop Cola magic isn't that visually creative nor does it play with the fact that it's fueled by soda. Fred C. Stresing's color art still holds up well in this issue, as the color palette is still that purple-and-green-centric weirdness for which this franchise is known.
Invader Zim #29 still has some solid jokes to throw out, but it has more duds than usual. It's not bad, and, if you follow this series, it's still worth picking up. Otherwise, it's not worth grabbing.