have this ms paint rendition of what i did to achieve that . each black arrow represents an object being parented to another one
each segment of the umbilical consists of one big rectangle with a circle stuck at the end of it to act as a joint . each rectangle is parented to the circle right behind it , and each circle is parented to the rectangle preceding it . just like in the image
there's also the joint that connects five pebbles to the umbilical ( which the base of his body is parented to ) and the joint that connects the umbilical to the wall slider piece !
this means that when i rotate a joint , all objects after it will rotate along with it ! i moved pebbles around by rotating the joints to the angles i want them to be at ( the joint connecting pebbles to the umbilical also served to keep him upright by rotating the other way )