mindblower

/ˈmaɪndˌbloʊər/
noun
  1. Something that is extremely surprising, impressive, or shocking; something that amazes or astonishes.
    • The ending of that movie was a total mindblower—I never saw it coming.
    • Her explanation of quantum physics was a real mindblower for the whole class.
    • The magician's final trick was a mindblower that left the audience speechless.