At least Stun Spore will give them trouble before it goes -- if it didn't keep missing 50% of the time like it's been doing today. I'm debating whether to put HP Ice or HP Fire though. It's a hard choice, seeing as the cotton ball can counter only so many walls with any one. With Ice, it can hard counter most dragons, many other grass-types, and flyers (such as the genies). Fire can beat other Grass-types that plague the tier, obviously -- including its nemeses Ferrothorn and Celebi.
Which one is best?