Level the Prismatic Missile to max and the Crown to max (5), then pick up a chest after the 10 minute point and it will evolve into the Luminaire. I like to use the Moongolow map on Hurry (so that it really only takes about 5 minutes) since you can just go grab the Crown from the start (at the spawn, should be in the group of items in the top left corner of the spawn area) and then start working on leveling it to 5.