Due to an unfortunate mishap from when Grody's great grandfather, Rancor Grungus, experimented with highly radioactive materials without a protective suit, the Grungus family line would be rendered sterile. However, to mitigate this, Rancor did dabble in cloning technology and genetic manipulation, which would be later refined by Grody's grandfather, Vile Grungus, and perfected by his father, Atrocious Grungus.

Atrocious expected young Grody (then named GC-289) to be an exceptional heir to the Grungus family name.

... He was wrong. Very, very wrong.