It sounds like it has rotted (the base). You can propagate via stem cuttings. I'm not the best person to answer how to do that (someone else should chime in), but Kalanchoe's are easy to propagate that way.

What you're describing sound like aerial roots. Some succulents are notorious for throwing out aerial roots (air roots I believe is another term for them).

Whatever soil you chose to use to propagate your stem cuttings with, be sure that it's fast draining. Whatever soil your Kalanchoe was in before could of been staying wet too long and caused its demise; you don't want to kill off your stem cuttings too by using poor draining soil.

Planto

I agree that a slowly turning black stem sounds like rot.
I would cut off a healthy piece of it, let it air dry for a day, then plant it in some loose, well draining soil. I think kalanachoes can root even from a single leaf, so I think if you cut off several healthy pieces of stem with a few leaves you have a good chacne of saving this.

Thank you guys I tried that and it still died actually both of mine did or the one is in the process of. All of the nice branches shriveled and now it looks bad u watered it and stuff so I don't know why it did that and they both did it at the same time do you think the weather change could have shocked them? It was a really rough winter and I noticed towards the end they were not doing so good I'll check on the one tommorow and update thanks for the help.

It sounds like it was too far gone to be saved.

Planto

It is good to cover anything that hasnt any roots so that it does not dry out in the process of regrowth. I like to cut the bottom off of a clear gallon water jug and set it over the top. For a kalanchoe, I would probably leave the cap off. Dont put it in direct sun while it is regrowing, but put it in the brightest light possible. If you dont have a bright spot, you can also train a light on it, for instance a CFL (compact fluorescent). It just needs enough light for energy to grow roots.

I would use cactus soil for a kalanchoe. If the mix starts to dry out while the cuttings are regrowing, just mist the surface with a spray bottle. You dont want it to be wet, a little moisture goes a long way.

Cuttings dont need a lot of care. Just set it and forget it, checking occasionally to make sure the soil has not completely dried out. They can dry up and get floppy/wrinkly and still be alive. If the plant is really dry right now, mist it with a spray bottle and put it in a humid area for a few hours, like a plastic bag. It might perk up a bit. Once it reroots it should start to pick up.

thank you I took the latest kalanchoe plant that started to die and took all the branches that had growth, put them in pots with a light covering of dirt and watered them. I left them on my porch for about a week and they look good! Thank you for your advice