Did Big Mom actually use the new level of Armament Haki that was introduced in the latest chapter against Gear 4 Luffy?
Most of us assumed that it was the power of her devil fruit that knocked Luffy out of Gear 4, but the new information about Haki shows us that it can be used like a virus or an acid. Big Mom may have transfered her own Haki into Luffy and “broke” down the Haki concentration from Luffy’s fist.
*Theory by ogag47