What is this light artifact on my pic?

Question

Took a pic with my 35mm Nikon lens last night, and got this light artifact. Is this something normal? Reflection? Is it dirt on my lens? How do I prevent this from happening? I think it only happened when there is backlighting.

UPDATE: new screenshot.

Answer

Looks like lens flare to me. Odds are there's a similarly-shaped pattern of lights in front of the camera (possibly behind/above the subject since you noted backlighting) and what you're seeing is a result of those lights being bounced around inside the lens. update: Now that you've posted an updated photo, one can see the chandelier which is being reflected either by the lens itself or possibly by a filter on the lens.

For more information, see the lengthy answers to What causes lens flare?

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