As we know, the last chapter of "Game of Thrones", "Beyond the Wall", was a roller coaster of emotions. We thought they achieved the goal, when the White Walkers attacked them. The lake saved them, but it froze and they were able to advance. Daenerys came to save them and Jon became the hero, fell into the frozen water with thousands of dead and, worst of all, killed Viserion to turn it into a zombie dragon.
And the latter is what has raised a suspicion. How could the King of the Night have known he had to get there with that ice spear? The only thing that could kill one of Daenerys' beloved dragons was a gigantic arrow, and although he often appears in the series with her, now what is striking is that three of the leaders had spears. That is, the exact number to kill Dany's three children.
So would it have been that the King of the Army of the Dead had used his own telepathic powers or his connection to Bran to know that Jon's group was going to travel north of the Wall and seized the opportunity to add a dragon to their ranks?
It is also suspect that the group of dead who were walking on their own did not catch the "suicide squad" before the others arrived. And it is also interesting that they never tried to cross the lake, even a few to try if it had already frozen. It had to be the Dog who gave them the green light. It seems like they've been expecting something ...
Ah, and above, they had in their power gigantic chains to draw the dragon out of the water. Curious, is not it?
If this was indeed a trap, then a very black future awaits us, since it would mean that the King of the Night knows enough things. We have already seen him interrupt Bran's visions, and even he could touch one of them (and leave a mark on his arm).
What do they believe? Will it have its own abilities or will it be introduced into the mind of the three-eyed Crow?