Not sure what this event challenge is supposed to actually be about, but I’m getting credit for it no matter what I do in a battle or what mode I’m playing. I doubt that’s intended.
Create jack-o-lanterns is when you use the pumpkin ability in hallows end missions.
Hm. I figured that was the case, but the game never refers to them as “jack o’ lanterns” anywhere else, only “pumpkins.” Either way, doesn’t change the fact that I was erroneously getting credit for the challenge while not doing the Hallow’s End missions, and thus not having access to “Oh my Gourd.” Got hundreds of instances of it before ever trying those missions even once.
If you use your normal plague bomber mini he also counts for this, same with HH, regardless of where you play them.