This is one of our favorite classic cacti. Mammillaria plumosa is a flowering cactus species native to Northeastern Mexico. Most notably known for its fuzzy downy spines as they actually are touchable since the spines grow inwards. They resemble a little cloud which is why I think we love them so much. These are a must have for anyone just getting into cacti.
You'll wanna let these dry in between waterings completely then when dry give it a nice good watering. These need to be in a well draining cactus mix and in a nice bright window/area.