Upside down text

Substitutes each letter for a character that looks like it rotated 180 degrees, then reverses the string so it reads correctly upside down. ǝpᴉsdn uʍop.

The characters come from all over Unicode and none of them was designed for this. The upside-down "a" is a turned a from the phonetic alphabet, where it represents a specific vowel sound; the upside-down "e" is a schwa; the upside-down "M" is a plain W. Because they are scavenged rather than designed, a few letters have no good match and the illusion depends heavily on the font your device picks. Reversing the string is the second half of the trick — without it the letters are flipped but read left to right, which does not look rotated at all.