Euphorbia ammak, it likes as much sun as possible, extremely drought tolerant when established. The area you have it in now is not enough sun for sure

Is it double potted? It doesn't look like it but not sure. The pot has a hole? It's beautiful but I don't know enough to advise you except it probably should be repotted in a fast draining mix unless the seller has done it recently. It looks great in that spot, but could you relocate to a very sunny window?

Agree about it needing more light than where it is now. (Also, not technically a cactus, though it sure does look a lot like one!)

It looks like a plant I almost got that had a warning about the sap irritating the skin if touched. I don't recall the name so couldn't say if it's the same. I didn't want to risk a kid or pet getting into it. It's a zoo around my house.

Yeah, you will need to watch for the sap on any Euphorbias, and be very careful when moving or transplanting.

Thank you all!

I will be moving it to a western facing window that gets a lot of afternoon light tomorrow (as soon as I get the plant-caddy to make it easier to rill across the living room).

Incidentally, the store that had the plant for the past several years tells me they never placed it in sun and watered very infrequently. But, I don't see how sun would harm this succulent :-).

It is also not double planted, but the small pot in which it is planted is placed inside the outer pot that doesn't have irrigation (the small pot drains into the white one).

Any advice regarding watering? The consistent guidance I am getting is to water the plant when the dirt gets fully dry, but with such a small pot this can happen quickly...

You'll have to be very careful not to have it sitting in water which stays in the bottom of the white pot. That's the proverbial "recipe for disaster." Lifting it out to water and drain would be best. I realize it's awkward to handle.

I hope someone will chime in here as to whether it needs to be in a slightly bigger pot.

I realize you must have been delighted with how the plant looks in that corner, but if you leave it there and there is not enough light, by the time you realize it the plant could be negatively affected. In the store, it's possible that there was store lighting on it many hours a day, so maybe that's why it did so well.

How quickly it dries out depends on the soil, your humidity, how much light it gets, time of year--lots of different factors. You can stick a skewer into the soil for a while and pull out to see if it's damp.

Thanks again folks. I moved it closer to the large western facing window in my living-room, closer to other plants too... I also removed it from the white pot for better drainage. I will get a new 'holder' to both allow for future irrigation and also provide the right balance, should it tip over... Here's hoping it will thrive.

It could be a Euphorbia, but to me it looks more like a Cereus peruvianus. Could you post a close-up photo? The same general advice would hold true, but you would not need to worry about the sap.

Here are some close-up pics...

Thanks again! (that's a massive column! and I don't live in a loft haha).