Skyfire is a unique word, and it's challenging to find synonyms that can convey the same sense of wonder and awe that this word does. However, there are a few phrases that come to mind that could work as synonyms. For instance, the term "celestial inferno" could be used to describe a phenomenon that resembles skyfire - perhaps a meteor shower or a particularly bright aurora borealis. Another option could be "celestial blaze," which could be used to describe an unusually fiery sunset or sunrise. "Heavenly pyrotechnics" is another phrase that could fit the bill, particularly when talking about a particularly dazzling fireworks display at night. Ultimately, while there may not be a perfect synonym for skyfire, a few inventive turns of phrase can come close.