Just thought I’d clear something up.
It seems many people are totally perplexed by Nanimon’s design (and justifiably so).
Nanimon is a virus Digimon who is classified as an “invader” and has an appearance that suggests that of a strange, middle-aged man with muscular limbs and seems to have a sort of “bad boy rebel” thing going on.
Nanimon’s name comes from “What?” (何? Nani?), which clearly alludes to his bizarre appearance and nature.
In the Digimon lore, it is said that Nanimon had a love of alcohol, but has since gone sober and cleaned up his act. Many fans of the original Digimon anime remember Nanimon for his one major appearance on the show as a foul-tempered physical trainer and “motivator” hired by DemiDevimon to ready Myotismon’s troops for the invasion of Earth. Even more people will remember how he was dealt with by the heroes, which was getting him drunk on sake (or, in the English dub, getting him “drunk” on soda).
It is also said that Nanimon comes from another world entirely, and has trained himself to survive in the harshly competitive Digital World.
Now, the moment of truth:
Nanimon is, in fact, inspired by the Tamagotchi character Oyajitchi.
For those who are unaware, Tamagotchi is, like Digimon, a virtual pet in which you raise strange creatures. However, Digimon has more of an emphasis on not only raising, but battling your pet creature head-to-head with your friends’.
Anyhoo, Oyajitchi is, like Nanimon, a sort of joke character, and his name comes from oyaji, which means “one’s father” or “old man”.
Oyajitchi, according to some sources, is said to have an addiction to alcohol (particularly sake) and is a “lover of beautiful women”.
Also, both Digimon and Tamagotchi are properties of Bandai.
So, there you have it. Nanimon is actually Oyajitchi, who somehow escaped from the Tamagotchi world, kicked his sake addiction and trained himself to fight fearsome monsters in the Digimon world, creating a new image for himself in the process.
tldr: Nanimon is a Tamagotchi reference. :P
And here are Oyajitchi’s and Nanimon’s v-pet sprites for comparison: