Wizard of Oz

noun2

1. •
   A person, believed to have magical powers because of awe-inspiring displays, but, as ultimately revealed, ordinary.

   • I'm not one of these people that say, “Listen, we should bow down to the Wizard of Oz ’cause we don’t know what’s going on behind that curtain.” — 2006
2. •
   [before a noun] A person simulating the operation of a supposed intelligent device, usually in an experiment.

   • The goal of Neimo is to provide designers with a "Wizard of Oz" environment to observe and evaluate how users interact with multimodal interfaces. — 1992