Iyami Has Arrived is the thirty-first episode of Osomastu-san.
Matsuzō and Matsuyo went for a hot springs trip, deliberately leaving their sons behind with a few thousand yen. Osomatsu tries to claim them for gambling but the others stop him from reaching Choromatsu, who keeps the money.
Suddenly, Iyami enters the Matsuno household door and begs for food. The Sextuplets initially resist him, but Iyami helps out by devouring all the garbage from the Sextuplets (complete with new techniques of defecating in a totally clean and environmental-friendly way). The Sextuplets eventually help him out, give him money to play / gamble, and even allow him to sleep together at night.
Upon getting their promise that he can stay as long as he wishes, however, the next morning Iyami wears Osomatsu's clothes and starts to behave bad again. The Sextuplets tries to attack him with words, but the words cut open them instead, because they are exactly what they criticize about.
With all six brothers lying unconscious (presumably dead), Iyami successfully leave the house with everything from the Matsuno household. He triumphantly says "Evil would be punished", but the word becomes such a big weapon that not only Iyami, but the entire Akatsuka city is destroyed.
- Whenever Iyami shows sign of sloppiness or failure, Osomatsu and Karamatsu exchange insults at each other, saying the other "not to end up like this". In addition, Karamatsu doesn't address Osomatsu with the "niisan" (older brother) suffix during these exchanges, as younger brothers usually do.
- The way that Iyami gets destroyed is similar to Kid Buu's demise in Dragon Ball Z.