Synthetic marijuana—often called “Spice,” “K2,” or “fake weed”—is not the same as natural marijuana. Instead of coming from a plant’s natural chemicals like THC and CBD, it’s made by spraying man-made chemicals onto dried plant material. These chemicals are designed to copy THC’s effects but can be quite different. They often stick to brain receptors more strongly, which can lead to much stronger and unpredictable effects.