This is a caudex euphorbia, categorised as medusoid, because the various branches look like a bunch of snakes. A caudiciform plant has a fat, succulent stem and root system for storing water and are also referred to as "fat plants". This particular Euphorbia is found growing in between rocks, just likes this one, which I photographed in the bush gardens at The Aloe Farm, an aloe nursery in South Africa that I visited in August.
Although I grow many succulents, I'm quite good at killing Euphorbia. This is because you have to get their water requirements exactly right and if you overwater them, they promptly rot. They like water regularly, but only enough to dry out very quickly.
omg