Hard to tell. I want to say Trichocereus/Echinopsis hybrid based on the larger stems. The one thing it definitely is, is hungry for more light.

It looks like E. chamaesereus, but it’s not. This cactus is all one cactus. At a quick glance it does look like two different cactus. This cactus is etiolated, including its babies, and would look like a completely different cactus if it had recieved enough light. When etiolated the growth is very weak, even the spines are weak. I’m thinkin maybe Echinopsis oxygona or some hybrid like Echinopsis ’Los Angeles’, but it is really hard to tell. Definitely an Echinopsis tho🙂.