Tang San went to get it back, because he would never come back by himself. If this operation is reasonable, then there is only one explanation that makes sense, and that is the weight setting of the trident. We know that when the trident is only in Tang San's hands, it weighs 108 kg, and when it is sold, it is 108000 kg. Therefore, after Tang San was thrown out, it basically became a rivet, and it could not be collected from a distance.