In 2012, Science Forum created a trippy video of optical illusions designed to produce natural hallucinogenic effects after viewing. I can attest that watching the video does, in fact, trigger temporary dizzying effects (they seem to go away in about five minutes). Be sure to view it in HD and in fullscreen to start the wild optical ride.
Hallucinogens are a general group of pharmacological agents that can be divided into three broad categories: psychedelics, dissociatives, and deliriants. These classes of psychoactive drugs have in common that they can cause subjective changes in perception, thought, emotion and consciousness. Unlike other psychoactive drugs, such as stimulants and opioids, these drugs do not merely amplify familiar states of mind, but rather induce experiences that are qualitatively different from those of ordinary consciousness. These experiences are often compared to non-ordinary forms of consciousness such as trance, meditation, dreams, or insanity.
Depth perception is often heightened and perspective distorted; inanimate objects take on expressions, and synesthesia (hearing colors, seeing sounds, etc.) is common. Time may seem to slow down enormously as more and more passing events claim the attention, or it may stop entirely, giving place to an eternal present. When the eyes are closed, fantastically vivid images appear: first geometrical forms and then landscapes, buildings, animate beings, and symbolic objects.
Hallucinogens, such as LSD, make you unaware of and indifferent to your surroundings, causing you to be an unsafe driver. These drugs cause you to see and hear things that aren't there, messing up your ability to detect danger and make good decisions. These drugs can make you feel like you have super strength, causing you to be aggressive behind the wheel.