This happens all the time, in fact I saw it last night as well. A
Halo around the
moon is Perfectly normal.
Actually
Sun Dogs are caused in the same way as the sun is low in the sky and the light is refracted
through moisture in the atmosphere. This gives the impression that there are two suns. Look at most footage closely and you often see a halo with
these as well. It's rare though because conditions have to be just right.
There are many threads on ATS surrounding 2nd sun/Elenin/Nibiru etc which use a sun dog as the basis for their doomsday hypothesis but it's all
nonsense. In fact sun dogs usually produce TWO extra suns as the light is bent either side of the actual sun.