Mark of the Beast

The mark of the beast is contrasted in the Book of Revelation with the mark on the foreheads of the righteous.

In John's vision, the mark which he saw the angel putting on the foreheads of the righteous was a visible mark, not invisible. But we know that was a symbol - because angels aren't going around visibly marking the foreheads of the righteous. It really meant God knows those who are His.

So the mark of the beast, like the mark on the righteous, was visible too in John's vision - it wasn't something invisible like an implant. And like the mark on the righteous, it was symbolic. An implant wouldn't look good under the skin of the forehead - it would stand out like a sore thumb! The mark of the beast probably really just meant that the political system would begin to discriminate against Christians.

So we probably needn't be expecting that a physical mark, much less an implant, must be the fulfilment of Prophecy.

That helps makes sense of the passage for all time, and can spare us a lot of flopped predictions.

Don't confuse vision with fulfilment, symbol with reality.