Originally Posted by Mjölnir
We don't know but I don't see it being anything other than three random kids that happen to come onto something supernatural.
Maybe, but in the first shot of the kid walking up to the truck (to me) it appears that the headlights are at about at his hip level (but I suppose it could be only the angle of the shot making it seem that way) and the truck does not appear to be moving. Then in the 2nd shot we see him removing his hand from the trucks bumper and that the headlights are at about his chest height with the top of the bumper below the lights at about his lower waist, with still no movement. Then in the third shot it appears that the top of the Bumper is more at his upper waist and maybe even chest, and while we cannot see the headlights by relationship to the previous shots one would assume that they are at his shoulders and neck area. So, while I do not see physical movement in the vehicle until the last shot, the relationship to the height of the vehicle to the character seem to suggest that it is raising up in the 2nd and 3rd shots from where it started in the first. So, basically from what it appears like to me we have the headlights at his hip level on the first shot, the headlights at his chest on the 2nd shot and the headlights at his shoulders and neck on the 3rd shot (before the vehicle starts spinning). But who knows it is probably just the camera angles playing tricks on me.