Oh! My Googling efforts led me to Coryphantha! Gee.. IDing is so difficult! Haha! Thanks!

EDIT: I googled Mammillaria Karwinskiana and I think that's it? You think so?

I wish I knew the term for the fluffy white parts of a cactus. I'm intrigued with how the fluffy parts on yours are in between the spines and not under the spines like most cacti I've seen.

Maybe mammillaria mammillaris :)

You might want to go to cactuspedia.info and check out the mammillarias.

I'll google more now! At least I think we're all in consensus that it's some kind of Mammillaria..

@ealdwood, as long as nobody says that the white stuff is an aphid house in every crevice, I'm good with it haha! But yeah I know what you mean.. Even in Google photos the cotton is on the spines, not the crevices.. So I had a hard time with narrowing down an ID!

Mammillarias are tough to ID. Mammillarias.net has a good list of species descriptions and pictures. They also have an ID forum, although it is not very active. M. karwinskiana is certainly a possibility.

As for the fuzz, it is perfectly natural, but the reasons are a little complicated. All cactus have areoles, spots where all new growth starts. Spines, fur, flowers, fruit, new stems, even sometimes leaves grow from the areoles. In most cactus there are single areoles at the tops of the tubercles or along the ribs. Mammillarias are different. As the tubercles develop, the areoles divide, with one piece at the tip growing the spines, and another in the axil (the low point between the tubercles) growing everything else. Some species grow wool or bristles in the axils, others don't.

It is a good -looking plant, whatever it is!