Thankfully, these flutter-bys have not mutated into giant winged beasts that can breathe fire and bleed acid and steal your credit card information and knock over the Statue of Liberty; they have mutated into shittier versions of regular butterflies.
A study published in the journal Scientific Reports found that pale grass blue butterflies (Zizeeria maha), who were larvae when the Fukushima meltdown occurred, grew up to have malformed antennae, irregularly developed eyes, and wings much smaller than those of butterflies collected in areas not exposed to radiation. Researchers suggest that the radioactive material released into the environment was responsible for the mutations, though it seems hasty to rule out the possibility that God singled out these specific butterflies for punishment.
Project leader Professor Joji Otaki told BBC News that the findings were surprising.
"It has been believed that insects are very resistant to radiation. In that sense, our results were unexpected."
Looks like "insects can survive a nuclear holocaust" is just another lie butterflies made up, like when they told everyone their dad was a pilot in Russia.
However, just because the butterflies are flopping around like drunk sailors with tiny wings and crazy eyes, does not mean they are harmless.
A butterfly, even if it is not a teenage mutant ninja butterfly, is still a bug and bugs are gross. For example, when they fly at your face like they want to kick you or kiss you or blegh blegh ugh I hate them.
If you encounter a butterfly in the wild, you are advised to incinerate it with a blow torch or take shelter in a nearby powerplant.