I accidentally swallowed some food coloring.

This one-liner tickles our funny bone by playing on the literal and metaphorical meanings of "turning a color." We commonly say someone "turns red" when embarrassed or "turns green" when sick, using colors to describe emotional or physical states. The joke cleverly takes the actual act of consuming food coloring and then applies that same "turning a color" phrase, but this time implying a literal, physical transformation of the person's skin, which is, of course, delightfully absurd.

Food coloring itself is a common household item, used to brighten up everything from cakes and cookies to drinks and craft projects. We're all familiar with its power to dye things vibrant hues. The humor in this joke stems from the unexpected leap from dyeing food to dyeing a human, tapping into our everyday knowledge of what food coloring does and then twisting it into a silly, impossible scenario that makes us chuckle.