This is the tuber from a "small" Ipomoea macrorhiza vine.
This one didn't bloom this year but the mother plant did, I assumed at first glance that this was "several" plants because it had at least 4-5 vines popping up out of the soil. I decided to make a trade with "one" of the little vines and when I started digging....this is what I found!! This is the size of a baseball!! So I just wonder how big the "Mother plants" bulb is?!! I'm sure it has to be at least the size of a grapefruit!!
Common name: Pink Moon Vine
Family: Morning Glory
Plant Link: http://plantsdatabase.com/go/53206/