An imugi (이무기) is one of Korean folklore's most specific and evocative creatures: a giant, python-like serpent living in water or deep caves, said to be capable of becoming a true dragon if it manages to catch a yeouiju — a wish-granting jewel that falls from heaven — after enduring a very long wait, sometimes described as a thousand years.
Because of that legend, an imugi dream is read almost entirely through the idea of potential still in progress — real power and promise that hasn't fully arrived yet, unlike the dragon dream elsewhere on this site, which represents fortune already at its peak. Seeing an imugi is generally read as being on the right path toward something significant, without having fully arrived.
Watching an imugi actually transform into a dragon within the dream is read as one of the more thrilling, favorable sequences available in this tradition — years of effort or waiting finally paying off completely, echoed in real life as a long-delayed achievement or promotion finally landing.
An imugi that fails to ascend, or is interrupted before catching the yeouiju, is read more gently than a straightforward failure — closer to a near-miss than a real setback, since the legend itself treats the imugi's long wait as normal and expected rather than a sign anything went wrong.