702: Zeeky Boogy Doog

Explanation
The comic edit's joke comes from a combination of Touhou memes and a running gag from The Demented Cartoon Movie. The meme involves the joke that in order for a Touhou fan comic to be considered as such, it has to have a scene of the Scarlet Devil Mansion (home of Remilia Scarlet and partial setting of Embodiment of Scarlet Devil, the sixth Touhou game) exploding. This meme originated in the original Bomber Grape comic, which states that having either the Scarlet Devil Mansion or the Harukei Shrine's donations box exploding is a good way to add a punchline to a Touhou doujin. The last panel of the original Bomber Grape comic also has Sakuya Izayoi's chest padding explode, a reference to another Touhou meme (not as popular nowadays as it was years ago) that claims that Sakuya is flat-chested and pads her chest to make it seem bigger than it actually is.

In the comic edit, the last panel featuring Sakuya was replaced with a screencap of The Demented Cartoon Movie. The Demented Cartoon Movie is a 2001 flash movie infamous for a running gag where the Earth explodes or crashes into the sun for various reasons, often due to a nuclear explosion. Zeeky H. Bomb, a character from the flash movie, is a common cause for these explosions, as whenever he or any other character utters the words "Zeeky Boogy Doog", a explosion happens. The Earth was even exploded a couple of times due to the Zeeky words being uttered repeatedly or broadcasted all over the world.

The author writes
Finally, a comic that combines two of my favorite things: Touhou and old Flash cartoons from 2001. Can't believe the Demented Cartoon Movie is over 20 years old now; feels less than that!

Original comic: "Punchline" by Bomber Grape (translated from Japanese). Screencap from The Demented Cartoon Movie.

Transcript
{This comic reads from right to left} Title: Punchline Kaguya: Eirin, we've got a problem. We're out of joke material for this manga. Eirin: Not to worry, Your Highness. Just have the characters say any old thing, then in the last panel, draw the Scarlet Devil Mansion or the Harukei Shrine's offertory box exploding, and you've got yourself a Touhou manga. Kaguya: I knew you could do it, Eirin.... {Three explosions occur in sequence: first the Scarlet Devil Mansion, then Reimu Harukei's offertory box, and then the Earth for some reason}