Leuchtenbergia principis, also known as The Agave Cactus. This one is very fussy when it comes to drainage. I pot them in a pot with a large drainage hole, a few crocks in the bottom and a very gritty well drained mix. I also prop the pot up after watering to let it drain properly. It's not that they don't like watering, they enjoy a good soak, they just don't want their roots staying wet. I've not grown them from seed yet (The seed I bought online turned out to be Echinocactus grusonii 🙄) The smaller plants I have bought have both had shrivelled tips, probaably as the plants didn't like the watering they got. After repotting and sticking to a watering regime they have recovered well and are showing good new growth. They like a lot of light but benefit from a little shade from the midday sun. I feed once a month in the summer with dilute tomato feed.