Here are some pictures of the two stalks:

right above ground: http://twitpic.com/6rzdy
a couple of inches above ground: http://twitpic.com/6rzh6

Are you growing them amongst onions? The leaves in the background of the 2nd pic look hollow like onion or shallot leaves, whereas garlic leaves are flat or cupped.

Also, how deep did you plant them?

This happened to me a couple years back. It's occasionally manifested in certain softneck varieties after unusually cold winters. Scroll down to "Softneck varieties" on the page linked to below.

Here is a link that might be useful: Growing Garlic in Minnesota

korney19: Yes, I'm growing them amongst onions. I planted them about 2 inches deep. I did some careful digging and there is also a regular bulb a couple of inches in the soil, so the pictures I posted are of a second bulb on the stalk.

dkmarsh: Thanks for that link. The description of a bulbils forming right above the bulb sounds like what I have. We did have an unusually cold winter here this year, zone 8. When it happened to you, did you still harvest the real bulb in the ground? The site you linked to said when this happens the bulb is 'unmarketable' but I'm not sure if that means it's inedible.

I pulled up half of my garlic harvest this evening and perhaps 5 or 6 of them had the same thing with anywhere from 3-5 very small cloves growing in the stem (a few of them busted the stem open) and it was anywhere from 2-4 inches above the ground. The bulbs themselves look fine. I'm going to use them to grow more garlic, just to see what those bulbs come out like. Mine were growing sort of near spinach, but that's all.

I am growing garlic for the 1st time this year. I am growing 4 different varieties. 3 hard neck & 1 softneck. This happened on my softneck garlic (irichilium red) but not on the hardneck. This is the only place i have been able to find an answer!

Thanks!!

This happened on both my hardneck and softneck garlic this year (2021).

Stem cloves are a common occurrence in "soft neck" garlic varieties, in response to less-than-ideal growing conditions. Because of this, the presence of stem cloves usually signals a smaller than normal bulb. Stem cloves were widespread in my Artichoke garlic varieties during very wet years... garlic does not like waterlogged soil.

A raised bed can improve soil conditions & reduce the likelihood of stem cloves. With a raised bed, I had only one plant out of 150 form stem cloves this year.

If you get stem cloves, they are worth planting, since that may be a way of shedding diseases & organisms which can accumulate in the ground bulbs & be passed on.