A must-have cactus for your collection is the Bunny Ear Cactus, also known as Opuntia Tuna Monstruosa. This compact yet tall plant can be grown indoors with semi-shade and requires watering once every 5-7 days. The Bunny Ear Cactus is an easy-going houseplant, covered in small, cylindrical tubercles, and is perfect for gifting, terrariums, tabletop decor, and office desks. This low-maintenance cactus will thrive if you keep it simple: provide bright, indirect sunlight, infrequent but thorough watering.