A mcguffin is a creature who is wanted by many organizations on earth, wars were waged through history to obtain a mcguffin and to this day they still are. People sacrifice their lives seeking or hiding and defending a mcguffin.
Mcguffins are creatures who evolved for the sole purpose of being wanted,rare in nature they are not bred or farmed and they are not eaten.
People are attracted by the mcguffin, they just want one, even at the cost of killing people and risking their death, finding a single mcguffin is incredibly rare and finding two takes the effort of a nation, but even then...mcguffins can't be forced to breed, just like pandas they show no interest in sex. Fortunately mcguffins last a very long time, some mcguffins were killed by terroristic attacks but no one has ever seen a mcguffin die of old age. Nations across the world pride their mcguffins, and some of them are as old as human civilations.
How do I explain why the mcguffin evolved to be wanted by humans in the first place?