Possibly Epiphyllum oxypetalum (Queen of the Night) which is an old pass-along type epiphytic cacti houseplant. Have you ever seen it bloom? Does it bloom at night?

It could be quack grass.

Fertilizer most likely has nothing to do with corking, I asked about what you posted. Is that fertilizer ready-made solution or concentrate to be dissolved in water? Instructions for 'squirts' sounds strange to me but anything is possible (I am not suggesting that is your idea either). Questions I asked are about basic needs of succulents: free draining potting mix; container with drainage hole; lots of light; good air circulation. If these are supplied, the plant grows healthy and it is much easier to care for. Your plant doesn't look sick. Corking is natural. Plant is possibly bit lighter color than what it should be, but it is difficult to say for sure from a photo. If there is not enough light, the color usually gets lighter and plant starts to etiolate - stretch, trying to reach more light. It would grow 'skinnier' or with longer parts, and sparse spaced leaves. It will not die but could be weaker. Most important is good drainage: succulents should not have 'wet feet' - that could easily happen if the soil is too fine and it stays wet too long at the bottom part of the pot. It is difficult to tell sometimes, especially if potting soil contains too much peat that appears very dry on surface. Watering plant may seem to be appropriate, but it could be still too wet. If this happens and continues for extended period, it could cause rot.

Hi Melissa Chow, It may be a fungal or bacterial infection. In some cactus plants, I have seen these black spots spread through wounds.