Small fireballs appearing on League of Legends PBE server might be a tease of the next champion enchanter Milio, hinting at his release date. These small "fire buddies" were present in his description and depicted during the roadmap.
Usually, when such things arrive at PBE, the champion's release happens next patch. Currently, the test servers are preparing to the update 13.4, which. with a high probability, means Milio will come out in 13.5.
According to Riot Game's update schedule, they will release patch 13.5 on March 8. More details are likely to arrive soon. We know that Milio will be a male brown-skinned enchanter from Ixtal, appearing as a cute "Pokemon-like" creature. His ability kit was also rumored before, you can read all the details in our article.