Shrink and Motion Path...at the same time!

I wasn't able to get the effect I wanted, but here's what I used as a workaround:

1. Create two copies of your object, one to shrink and one to move.   Make the move one the size you want when the object is done shrinking, arrange it so it's on top of the shrink object, and give it an opaque background.

2. Align the two objects so that they have the same center, then move them where you want the object while it shrinks.

3. Time the move object to appear exactly when the shrink object gets to be that size.

4. Move the object.

I've attached the finished interaction.  The first object appears at 5 seconds, then shrinks and moves at 11.5 seconds.  I hope this helps, and I hope the next version of Storyline has a "shrink to a specific size" and "while you move" feature.