Strange objects appear in Solar and Heliospheric Observatory videos on a regular basis. The standard explanation is that they are video artifacts. Our specialists are unanimous: this is not a video artifact. But what it is--that's another question. Graded B.
Things are not always as they seem. The first thing that came to me? The sun is not reacting to the object, but I do feel that the object was there in anticipation of the flare. In other words, this object, whether piloted or remote controlled, is there to observe the flare and collect information.