×The food is not, in fact, for Sophie - it's for a snake. Eating makes snakes calmer, so you can get one of the yellow snakes to turn green. After that, tricking it into the path that leads to the roaches isn't impossible, and once it's in the right area it's reasonably straightforward to make it eat all the bugs. Meanwhile, I tricked the remaining yellow snakes into the lower right-hand passage, which leads to the edge of the screen and kills them. I never needed the orb to open the killing dead-end in the middle of the lake.