The Arch of Xyzzy (the previous version of Bow of Zyx) is a treasure in Bookworm Adventures.
Its ability is to increase damage to the letters X, Y, & Z in a word.
The Bow of Zyx has lesser damage increase than its upgraded version. Both of these treasures are designed as an arch or a bow.
Its name is a possible reference to Xyzzy, a cheat code in the text-based adventure game, Colossal Cave Adventure. Which is also a cheat code in Minesweeper