Many gamers regard the need for or use of mules in a game as a design flaw. In the game "Diablo II" 'mules' are sometimes used to 'smuggle' items from "Diablo II Classic" to "", the game's expansion—some items do not exist in both games. This type of smuggling is a one-way venture, as characters cannot make the return trip from "Lord of Destruction" to the 'classic version'. The use of mules in this manner circumvents the intended inability of characters to move freely from one version to the other, and some players consider this a 'cheat'.