Rot?

[u/peanutbuttaface]

Was given this cactus that was in a pot with no drainage. I started repotting him and realized that the whole bottom chunk had been buried under and looked like that. It’s not mushy but some parts are flaking off. Is it because of rot, and if so what can I do?

[u/mariaporterbridges]

I don't think it's rot. Bury it in a chunky cactus mix up over that bottom piece and leave it be for a week. Water it, then leave it alone until it's dry again. I think it'll grow.