How can something so absolutely beautiful consist of the deadliest poison?

Death Cap: A mushroom typically ingested to relieve one of their demons and other problems. The psychedelic properties make this mushroom dangerous, as the amounts consumed must be monitored and properly measured prior to use. These mushrooms can be used in spells or potions to aid in wiping one's memories and identity, giving room for a foreign influence to step in and fabricate a new identity or life from the shell of the being who consumes it—a puppet to its master, clueless of the truth of their reality. The effects can vary and require consistent use if one wishes to maintain the lucidity of the mushrooms, but be wary… overuse of the mushrooms will lead to certain death, as they are indeed extremely poisonous.