So if the caterpillar doesn't like completely dissolve, turn into butterfly soup, then abracadabra it's way into a new body, what is happening inside that bag of mystery?

所以如果毛毛虫不喜欢完全溶解，变成蝴蝶汤，然后如魔法般地进入一个新的身体，那么那个神秘的袋子里到底发生了什么？