User blog comment:Kogath/Monster Hunter X Discussion/@comment-26034899-20150909005023/@comment-26826688-20150909214947

That would be cool, but that would go beyond anything realistic in the series. Monsters from frontier couldn't even get any crazier than that (unless frontier actually does that). While some monsters are quite unrealistic, I don't know how a living creature could pull off shape shifting (growing organs/limbs/bones, changing it's body structure, changing it's mass, etc).

It could work in a non-canon spin-off tho. It could be a experiment gone wrong or something.