The rock was always there...until, one day, it wasn't.
The rock and the butterfly are a perfect fit. The butterfly takes shelter on the steady rock after hours of flittering and fluttering, and the rock loves to hear of the butterfly's adventures after a long day of sitting in one spot. Then one day the rock isn't where it has always been—and the butterfly is alone. It can't find a comfortable place to rest, and it eventually collapses on the ground. When it wakes, the butterfly realizes that it is lying in the exact spot where the rock used to be, and it takes comfort in all that its beloved friend left behind.