I don't know if you've heard this one's original form, but it's used to tell the difference between a King snake and a Coral snake.
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Sand that is black
Comes from no friend of Jack's.
Sand golden-yellow
Wielded by a merry fellow.
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Here's the original poem for all of you outdoorsy types.
"Red touches black, friend of Jack. Red touches yellow, killer fellow."
So if you're out hiking or whatever and come across a red, yellow, and black banded snake, make sure the red bands touch the black ones before getting too close. If you see red and yellow next to each other, run like a Rapidash.