Hypothesis: UFOs are from a parallel universe where an advanced civilization of humans is observing us and letting us know that their technology is vastly superior to ours and, if they so choose, could invade our world, and easily replace us. COVID-19 is either a test run or the real thing: a virus designed with death as a diversion; the real goal is to sterilize males and reduce humans in this universe to a manageable number or replaced entirely. The concept of a deadly virus transmitted accidentally or otherwise between universes was explored in Counterpart, the TV series starring J.K. Simmons that ran on Starz for 20 episodes across two seasons, from December 10, 2017 to February 17, 2019. It’s uncanny anticipation of the coronavirus was examined in an April 2020 posting on GIZMODO, which includes some jaw-dropping clips and images from the series: https://io9.gizmodo.com/the-underrated-series-counterpart-has-new-resonance-in-1842778506 Perhaps invaders from the parallel universe have been among us for months or years, spreading stories that the pandemic is fake and a plot to take away our freedoms: disinformation useful for spreading the virus. While there have been several reports suggesting COVID-19 may cause male sterility, they have received virtually no attention in the mass media. We should know in a few months if the male sterility concerns prove valid, unless, of course, the invaders have a plan to suppress that information.
There are an infinite number of universes, some where humans are more advanced, less advanced, or about the same, even ones where we don't exist. So, how did they find us among all the others? I think the argument, that there are more advanced humans, in other universes, that see us as an adversary, is interesting. It speaks volumes of what kind of species we are and what motivates us. Male sterility would lead to an extinction danger for humans. We don't yet have a way to use science and medical technology to take a human embryo and grow it in a test tube until birth right now. So we can't grow our numbers if men can no longer sire children. Although, if there were a breakthrough that expanded human lifespan to near-immortality, replacing the dying population becomes less urgent.
The invaders from a parallel universe might have two very different objectives: 1. They have judged us poor caretakers of our planet and believe they could do a better job, or 2. They intend to plunder our Earth of its resources and use the empty shell as a disposal site for trash and toxic waste from their universe.