Leo Harrison wasn't surprised by Riley's choice; the Nobulanight was much rarer than the Stellargast.
"If you want it to evolve into a Nobulanight, you need to teach it Ghost Fire first, and then use the Ghost Fire to temper its ring for a week. Once the ring splits into two, use a Dark-type Evolution Crystal at night to make it evolve."
Riley was a little bit puzzled, "Ghost Fire? Isn't that a fire-type move?"
"That's why you need to start preparing it while it's still a Little Cosmicub. Although it's a ghost-type spirit beast, its ring can absorb materials from different attributes, allowing it to use the ring as a medium to release Ghost Fire."
"With evolution, the ring's energy absorption capacity increases. If you wait until it evolves into a Cosmoteer to teach it Ghost Fire, the required materials would be ten times more than before it evolve," Leo Harrison explained.
Riley was caught off guard by this wave of information.