Maybe, you can't see the cactus... it's San Pedro cactus, a fast-growing columnar cactus native to the Andes of Peru. Old peruvian people used to recreating their imagination, maybe to see the future, it was considered like a "spiritual plant".
I guess, then to drink san pedro, you'd see the things like this pic ^^.
Wiki says: The San Pedro cactus is used as an entheogen in shamanic cultures of the Andes and more recently in the western world. The most common form of preparation is to cut the cactus into slices, boil it for over 7 hours and juice it into a green liquid preparation that is then drunk during the ceremony which usually happens at night.