Shape Key Value Change

I know I saw this somewhere but can’t find it. I am looking for a way to change the shape or curve of a shape key while varying the value. Say you were wrapping an elongated sphere with a covering using a shape key and while adjust the value setting, the elongated sphere appears through the wrap. So if there was a way to adjust the size or shape of the wrap in mid value, the shape key would adjust. I am attaching a not so great image to hopefully illustrate what I am looking for.

A shape key, by itself, only does linear interpolation AFAIK.
I recommend using modifiers for more complex geometry modification. Lattice and Shrinkwrap are good for this. You can drive the base mesh shape with the shape key, and then the modifiers will make the more fancy motion.

That is a good suggestion. These may not work for you, but here are just some other tools to consider:

Stacking shape keys - one takes over when another ends. This is tedious.

Non-linear drivers - the shape key would still move linearly, but not with respect to the input. Having different keys for the motion along each axis may allow you to make curved motions with this approach. The mathematics for this would be moderate.

I have found these useful for corrective shape keys. For instance, I can set the values of a corrective shape key for specific angles of a joint to maintain self-contact with minimum self-collision. And, when one shape key reaches the end of what it can accomplish on its own, I add a new key to “carry on the work.” But, I try to restrict shape keys to geometry tweaking rather using them for large-scale motion.

Thanks for the suggestions. I know I saw it in a video somewhere but forgot where it was located. I believe what I saw was AustinC’s idea of stacking shape keys but will give them all a try