After the Invasion
So you know how there’s all these posts about how aliens invade Earth only to realize that Earth is a death planet and/or Space Australia as the flora, fauna, weather, and natural disasters kill them off and traumatize them? Well, imagine that the alien invaders finally give up and leave Earth. What chases them off? I imagine that the resistance starts putting out information on cryptids. It’s the last straw for the invaders, especially since even the human inhabitants native to Earth seem to be confused about exactly how dangerous said cryptids are, and so the aliens have no way to be prepared to face them. Morale plummets (even further) and alien command has to call off the invasion due to the public outcry, making history as the first time this group of aliens has retreated from an invasion.
The surviving humans soon realize that the honor of chasing off that group of aliens has attracted a lot of attention from other groups of aliens. Some of these aliens are looking at possibly invading. Others want to work with humans to turn Earth into a space vacation-destination. In order to discourage invaders while simultaneously attracting curious tourists, much information about the animals most infamous among the invaders is made readily available to the alien community in general, along with a lot of information on cryptids. Information on non-cryptids and cryptids is presented to aliens in much the same way, and the humans never clarify which are which, so many invaders are too scared to try and invade, while many tourists are intrigued by the potential mystery.
Of course, the tourists are horrified to learn that the hippopotamus is not, as they had thought, a cryptid.