Mysterious Alliums

I have onion issues. I planted green onions from seed; in the past I've planted both onion sets as well as leek from seeds, and never have I successfully gotten what I thought I was going to get.

The current crop of weirdness features overgrown green onions and a flowery bulb-type thing. My son suggests harvesting seeds from this thing to replant. I don't know, maybe? I love that he came up with the idea on his own, so we'll try it.