The Machine (きかい) effect replaces Sabitsuki's arms and legs with robotic limbs. There is also a device attached to the back of her head. It can be obtained in the Star World.
From the Nexus (which you take a south), you go southeast till you see two tanned pillars surrounded by flowers. Go through them, straight past the next area, and you'll be in the Underwater World. Go south from the entrance, and you should be in a large and vast area. Southwest from the entrance (going past a small tanned building with an entrance), you'll find a collection of reeds that you can go through (these reeds should sort of resemble a face). Go to the center of these reeds and go south, there will be what look like rusty stairs. Go down them!
Down the stairs, the first door you hit is where the Machine effect is. From the door, go directly north until you see one single orange spot on the left side of your screen. Go right of that and slightly above you, there should be a desk you can interact with!
- The girl in the Monochrome World also sports a similar pair of mechanical arms and legs.