Which insect or animal mutation would you care to deal with if man created?

With all that goes on with scientific experiments, environmental pollution, etc, if certain insects or animals were affected in negative ways, which would you want to deal with? If by some mishap of man mosquitoes grew to be as large as seagulls and swarmed in aggressive packs would you care to deal with them? If not those, how about ants that grew to the size of pinto beans and had an appetite for metal, any metal other than gold or any metal blended with gold; the metal in vehicles would be food? The last choice of mutations would be pigeons that would drop acid poop that was powerful enough to eat through metal, concrete, stone, etc, and would burn through clothe, leather, wood, etc, like a hot knife through soft butter. Recap, you choices are:

• Aggressive swarming mosquitoes the size of seagulls.
• Ants the size of pinto beans that feast on any metal not of gold or gold alloy.
• Pigeons whose defecation is a severe and powerful acid capable of eating through almost anything.

Which mutation would you rather deal with due to environmental pollution or contamination, or some science experiment that escape the lab or when erratic?