But there’s no need to bust out the mad science conspiracy theories quite yet. This initiative, dubbed the “Debug Project,” is actually part of public health effort to fight the very mosquito populations that spread nasty scourges like the deformity-causing Zika virus.

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The skeeters in question are male Aedes aegypti mosquitoes, which carry pathogens that cause illnesses like Zika, dengue, and chikungunya. They aren’t genetically engineered—rather, Verily (in collaboration with MosquitoMate and Fresno County) cooked up a project to infect the bugs with the Wolbachia bacteria.

Wolbachia doesn’t affect humans. And, as a bonus, these male mosquitoes in question don’t actually bite (likely a huge source of relief for Fresno-area residents who are about to be inundated with the new mosquito pool).

But the bacterial infection has one major, advantageous side effect: Males carrying it which mate with female mosquitoes create non-viable eggs. That means that, over a long enough period of time, the Aedes aegypti population is expected to decline (hopefully reducing Zika incidence and risk in the process).

“This study will be the largest U.S. release to-date of sterile male mosquitoes treated with Wolbachia, a naturally occurring bacterium, and will take place over a 20 week period in two neighborhoods each approximately 300 acres in size,” wrote Verily in a blog post.

There have been a number of other mosquito-fighting efforts in Zika’s wake (public health officials have stressed that pest control is the single most important way to combat the infection’s spread, especially since developing a vaccine or other treatments could take years). For instance, Brazil, which has been hit particularly hard by Zika, has even tried out special billboards which lure and kill Zika-carrying mosquitoes.