what is happening here?

what is happening at the base of this mammillaria?

Interesting - maybe a bit early to say, but it looks like an offset going cristate / monstrose. I see that there is another offset, which looks normal ,on the other side. If it does turn out to be monstrose, grow it on, as there is a good eBay market for such things., unless you like those forms yourself, of course. You will have realised by now that I don't very much!

the plant sowed by prof. carlo zanovello is a mammillaria obscura var. tortullispina.
this is the other side....