Topic: Mystery Plant

[Patty S]

Does anybody know what this plant is? 
     

A few years ago, I thought it might be a Dahlia, but I've gotten Dahlias since then, & now I know that it's not.  (It's in front of a Dahlia in this pic.)
     

When we first moved here, I wasn't into flower gardening & didn't notice what was growing in the yard, so I have no idea if it flowered then, or not.  For the past 2 years, something has always seemed to need the space where it's been growing trying to grow, & I kept disturbing it before it could do anything.   I finally put it in the back yard bed last fall (so I'd leave it alone), but I still don't know what it is.  The are a couple more of them growing where this one had been, so it apparently makes new babies, underground.

It comes from a round bulb that looks like a small potato... in fact, at one point I thought it had to be a potato, & I even brought a few of them in & cooked them. (Uhhh... Keith didn't like it.  It's NOT a potato!)