If I have Slow Start and use Heart Swap/Guard Swap or any of those moves will the swap make a percentage of my stats counting Slow Start, and will the foe Pokemon recieve low stats too?
The Pokemon with Slow Start (presumably Regigigas) will have it's Attack and Speed stats up to full power once again, and the Skill/Guard/Heart Swapper will have their stats halved.
Hope I helped. :) Source
