Consider the neighborhood kid magician doing magical tricks for the little ones. It's not entirely unlikely that an amazing trick will include the magic word: Abracadabra.
The neighborhood magician is actually channeling Quintus Serenus Sammonicus and generations of magical practitioners before him, though Sammonicus was the first to actually write it down more than 1,800 years ago. The son of a noble family, Sammonicus later tutored the children of Roman emperors and recommended it as a magical remedy for fever.
In the second century A.D., Sammonicus authored Liber Medicinalis (Book of Medicine), a medical poem in which he advised writing the magic word on parchment and enclosing it within a downward-pointing triangle. According to his prescription, the word should be written repeatedly in 11 progressively shorter and smaller lines, with the only a single letter in the last line. The parchment would then be hung on the neck of the afflicted.
People really did rely on it as a magical remedy. According to National Geographic, numerous papyrus fragments bearing the magic word still exist. But questions remain: What does it mean? Where did it come from? On these points, the debate continues.
It could come from the Hebrew phrase "ebrah k'dabri," meaning "I create as I speak." Or perhaps it comes from another Hebrew phrase, "ha brachah dabarah," meaning "name of the blessed."
Author J.K. Rowling employed "avada kedavra" as the forbidden killing curse in her Harry Potter series. The undeniably similar phrase is Aramaic for "the thing that must be destroyed."