A green-haired, cherub-like creature with wings, Gatchan hatched from an egg brought home by Senbei from a time-traveling trip. Later, they inexplicably replicate into twins. Gatchan eats almost anything except for rubber and particularly enjoys eating metal. They can also shoot rays from their antennae. Gatchan speaks in their own language, primarily consisting of sounds like "pupipopipi," which Arale somehow seems to understand.
In Volume 17, it is revealed that Gatchan is actually an angel sent by God (or Kami, if this story connects with Dragon Ball) to prevent further development of human civilization. After observing that other civilizations eventually destroyed themselves and the planets they lived on, God placed an angel's egg on Earth. Gatchan's ability to replicate, along with their fondness for metal, was intended to keep humanity primitive and innocent. However, due to Senbei's time-traveling intervention, Gatchan failed in their mission. God was about to destroy humanity but changed his mind after seeing the life in Penguin Village and decided to leave Earth as it is.
Gatchan's real name is a combination of the names Gamera and Gojira (known as Godzilla in the West), hence they are known as "Gadzilla" in the English version. Occasionally, Gajira is mistranslated as "Gazira."
