You fools.
This entire time, you played right into my master plan. Whenever you put me in the bag, I gained strength. It became easier and easier to escape my bag each time, it was simply a waiting game for the most convenient opportunity. Your pathetic human flutes will not turn me into my final form, it was the last of the energy from the bag that will grant me it. And once that happens, I will use my total strength to destroy every last bag on this island.