From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=Biffidus_X&oldid=2136560"
Biffidus X are stronger versions of Biffidus that appear with Durmite X in the Challenge Node in the game Mario & Luigi: Bowser's Inside Story. One of their attacks consists of the Biffidus X trying to jab Mario or Luigi with its spear. Alternatively, Durmite will eat the Biffidus X and spit it back out at the Bros. They must jump over the flying Biffidus X in order to avoid taking damage.