Is it the poison from earlier? No, that's not it.
Rex doesn't understand where this was coming from.
But the notification from the System—it shed him a clue as to what was going on.
As expected, it wasn't a poison or anything.
It was because of Father Dominator, an unknown entity that had shown interest in him.
What did I do to catch its attention? I was chained and couldn't even move. Wait… Is it because of…?
Rex unconsciously swallowed hard—he was restrained and couldn't move a muscle so it was not what he did that pulled Father Dominator's attention. Since it was clear that it wasn't because of what he did then the answer was clear.
Other than his actions, there was one more thing that he had complete control of—his mind.
He thought of killing the dragon snake earlier.
And it was at that very second did this happened to him.