The Ultimate Fusion
Stark had been attacked by Leader around four times, while all he and his clone did was dodging all the attacks he sent at them, since they REALLY wanted him to despair.
Since the moment they saw him and his calm expression, they instantly knew that guy thought himself superior to all of them since he probably had power and influence in the outside world.
But Leader had forgotten just one simple thing: the outside world doesn't matter during the 'Domination Trial', you can be the king of a country, a president, a CEO, but you would still get killed if you didn't fight with all your might.
Plus, they knew from that simple combo with [Snake Restrain] and [Snaky the Snake], as well as his expression after they avoided it that this was probably what he did against all his other opponents, yet it somehow didn't work against Stark and his clone since… well… they weren't dumb?