Counter Gain makes the attack of the attached energy cost 1 Colorless less. So, if it was attached to say Marshadow & Machamp-TTGX, they can use the additional effect of their GX attack with just 3 Fighting Energy since the initial cost of the GX attack is now 1 Coloress less. What happens with attacks like Muk & Alolan Muk TTGX GX Attack though? The attack has no cost to begin with, but the additional effect is with any 4 extra energy. Would the Counter Gain count as 1 one of the additional energy, or would it have no effect since the cost of the move is zero energy to begin with?