Yes, the seeds will pop out and give you lots of onion grass babies. The good thing is that once they get that big, they're really easy to pull up.

Yes, you want to pull them up now, and if you put them in the compost, those little bulblets on top will all grow, so either dispose of the whole plant in the trash, or cut of the tops and bottoms and get rid of those, while composting the middles.

Good advice above. Pull and dispose of quickly. Those "bubbles" are called scapes, and they contain the seeds. The roots will also multiply. That is why garlic is sold in "cloves" or groups of pieces of garlic. If you separate those groups and plant them, they'll turn into a whole clove with a stem and scape at the top.

Martha

Why not let it grow? It's a native plant and it is also edible. We can't wait for early spring when the first green appears.
Also, if it is all over the place, what are you going to replace it with?

Absolutely, Nina. Not sure which you have, pretty sure ours is A. canadense. It can't grow as fast as we can eat it. Inside the scapes can be flower buds or bulbils (baby bulbs.) Any part that isn't too tough, (like the stalks holding up the blooms and bulbils,) is excellent for eating, including the bulbils, leaves, in-ground bulb parts.