Matucana madisoniorum

These tiny barrels are often flattened in shape, usually solitary, from high in the Andes of Peru, like all the cool cactus kids these days. They get orange/red funnel-shaped flowers, so I’m told, but I haven’t seen them yet, so I cannot verify this. But they do bloom young, and only get to around 4 to 6 inches across. Very rare in the wild because of over-collection, so get your specimen from a seed-grown source.