This fun character is known by many names: epiphyllum angulier, zig zag cactus, ric rac cactus, the orchid cactus and of course, fishbone cactus. It loves living in hanging planters where it can properly spread it's zig zaggy goodness. It's also safe for pets which is never a bad idea.
These cacti love bright indirect light most of the time but will appreciate a bit of direct sunlight in late summer to tempt it to make flowers. Do treat this guy like a desert plant and only water it once the soil is completely dry. This should mean that you barely need to water it in the winter.
Live plant in houseplant soil in a plastic pot
Length of the strands varies but is no less than 15 cm.