Cacti are deep green with black spines, and are usually three blocks tall. They are found in desert biomes, sometimes in large groups. Players and mobs alike can take damage from a cactus if standing too close.
Cacti can be harvested easily by hand, although an axe is the fastest method. They can be replaced as a full block, just like a wood block. This makes them ideal for building pit traps and the like. Cacti can also be cooked in the furnace, creating green dye. Cactus may also be placed in flower plots.