Rainwater mixed with oil from several junky mexican owned vehicles leaving a parking lot, creating a rainbow-like effect on the pavement.

When a person eats really shitty Mexican food so that a few hours later he or she - but mostly he, since girls don't poop - simultaneously shits and vomits from both ends. Once the purging begins, the person will get on their hands and knees, and the spewing will look like a rainbow.

A variation on the Dirty Sanchez sexual move, where the first participant eats a box of Lucky Charms 2-3 hours beforehand. This results in a more colorful and amusing feces.