Black rot on cactus?

Question

I bought about 10 cactus and succulents last week and replanted them in pots to keep on my outdoor balcony. Upon further inspection I’m realizing one cactus may be rotting? It’s on the lower part of the plant looks kind of like bar so I’m not sure if I should try to cut it out? I have other plants in the same pot so I don’t want it to spread to them.

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Answer 1

That is a very strange dead growth. I would remove it, and then wipe the area with peroxide to prevent further infection. Make sure to only water when fully dry to prevent any infection in the future.