I got bored and decided to watch hunter x hunter 2011 again and I noticed while they were in the "swindlers swamp " during the first part of hunter examination there was a butterfly called the "hypnosis butterfly" . I believe this is the animal that the chimera ant queen ate and passed on DNA from by phagogenesis.
If those butterfly are not only native to the swamp then that might be possible. Which chapter was that?
There were penguin and lion and some other weird animals that shouldn't be indigenous to the region they were in so even if the butterfly was only in the swamp it's not totally a stretch lol.
Most likely, and Youpi is based from some form of Magical Beast.