In this BBC News clip, a child seems to materialize just behind the woman speaking. WTF. Unfortunately this isn't likely a fun glitch in our simulated reality but rather something with much more insidious potential. From WAXY:
If you watch the woman's face at the same time the boy appears, you can see her expression morph into a smile.
This technique is known as a Morph Cut, a feature added to Adobe Premiere Pro in 2015, intended to smooth transitions in interview footage, removing unwanted pauses, stutters, and filler words ("like," "um," and "uh") without hard splices and cuts.
The results, when used appropriately in interview footage without a changing background, can be nearly seamless.
It's likely that BBC News used a morph cut in the clip above to tighten up the interview without changing its meaning. But it's also ripe for abuse and fully capable of altering the meaning of an interview, and in many cases, undetectable.
Another demonstration of the technology: