First off, forget that the caption on the video says that they're M&M's. As one commenter put it, "If they were M&M's the water would be brown like a rainbow shit." Even Skittles hopped in the comments with a "Dude these are Skittles." Fair enough.
Now that we've got that out of the way, let's focus on the visual delight that unravels as our eyes are treated to a psychedelic scene of colors as hot water gets poured onto a circle of Skittles. Here we see vibrant colors slither into one another in a kaleidoscopic fusion, treating our eager eyes to a hypnotic massage.
Make sure to watch this with the sound on, as the ooh's and awe-inspired reactions of the children watching in the video are an appropriate response to what we all see in the clip.