Cactus growing irregularly?
I'm pretty new to growing/gardening and this year I decided to create a little indoor cactus garden. I bought some plants at Lowe's and Home Depot. This plant didn't grow for the first several months, but then all of a sudden it has had quite the growth spurt! The new growth looks different than the shape of the original plant. I seem to remember reading somewhere that it was bad if it grew in an irregular shape. Possibly a fungus/disease of some sort?
What do you think? Could someone let me know if you think it is healthy? If not, what should I do? Also, do you know what type this is?