"can I plant it? Will it come back true?"
They are called bulbils. Yes they can be planted. It may take 1 year to become a clove of garlic, and 1 or two more to become a bulb. If you have more than one cultivar of garlic, it may be a hybrid or it may come true.
Joseph Lofthouse has taught me that if I plant a
tomato seed, I will get a tomato. I no longer worry over varietal purity. However if variety makes a difference to you, use your bulbils in your cooking! They will taste like garlic. Mmmm.