In the last submission, some creative liberties were taken, as Eiffelyte doesn't actually have the capability of devouring a monster in-game. However, the game's final boss, King Famardy, can indeed devour a player whole! Generally he'll start to use this attack once a third of his life is gone, though the closer he gets to death, the more often he'll use it.
Super Geon's fallen victim to it, and Famardy is taunting his giant nom by rubbing over him from the outside. *prrrr*