User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-4694695-20130830104825/@comment-4969421-20130830112227

If I remember correctly, it doesn't "revive" the monsters, but when a certain amount of damage has been dealt, (50% iirc) they do their death animation before going into Feral Wyvern Mode.

It reminds me of Phantom Doragyurosu.

But hey, I could be completely wrong.