Stare at the center cross while the lilac dots disappear one at a time. A green dot may seem to chase the empty space even though the video never draws one. Keep your gaze steady for several seconds, then blink and try this optical illusion again.
Music: "Ghost Dance" by Kevin MacLeod (incompetech.com), licensed CC BY 3.0 US. Excerpt trimmed to 30 seconds and mixed with this video.
Source: https://commons.wikimedia.org/wiki/File:Ghost_Dance_(MacLeod,_Kevin)_(ISRC_USUAN1100573).oga
License: https://creativecommons.org/licenses/by/3.0/us/deed.en