Hi Dmj!
Unfortunately, "Scallion Onion" is something of a meaningless name. Scallions are any kind of onion, harvested while it is still green, before it bulbs up. Were there any other names on the package?

no it just said scallion onions they were bulbs when i planted so basically it looks like there a bunch of green onions on top of the bulb i planted got them from walmart
i live in az as well.

If they were little bulbs--pea-size to grape-size--they are probably standard onions grown to be sold as "sets". They will eventually bulb up, but not usually until July, which could be a problem in the lower elevations of southern Arizona. They cook before they get any size! To use them as green onions, just harvest them at the size you like them. If they were clusters of medium-small brown or reddish bulbs, they may be Shallots, which will be ready around early September in northern Arizona, or will burn up around late June in southern Arizona--better to plant Shallots in fall in the low to medium deserts, but Wal Mart doesn't know that!