If a ball has been hit and has not yet touched the ground, then gets plucked from the air by a raptor (or a falcon, eagle, etc.) and dropped over the boundary, will that still score a six, or will it be a dead ball?
While the none of the Laws of Cricket or any of the playing conditions for any ICC tournaments cover this precise scenario, the playing conditions do cover the case of the ball hitting a camera suspended over the field; quoting from section 20.1.3 of the One Day International playing conditions as of June 2019:
In a match where cameras are being used on or over the field of play (e.g. Spidercam), should a ball that has been hit by the batsman make contact, while still in play, with the camera, its apparatus or its cable, either umpire shall call and signal ‘dead ball’. The ball shall not count as one of the over and no runs shall be scored.
Given that, I think it would be more than reasonable for an umpire to call dead ball in the scenario you describe.