Timelapse footage of growing fly agaric mushrooms (Amanita muscaria). When young, the familiar red cap is enclosed in an egg-like sheath called the universal veil. This common and iconic mushroom contains the psychoactive chemical muscimol, which can cause hallucinations, delirium and euphoria. It has long been eaten for these effects in its native regions, notably by the indigenous peoples of Siberia and Scandinavia. It grows in close association with the roots of pine and birch trees, and although native to northern forests it has been introduced worldwide alongside its trees.