It has not been officially announced yet, but I'm thinking the next event is actually the one we have not yet had. A dungeon crawler kind of thing.
ペロペロ大作戦 - ペロペロ催眠wiki ～我が頭髪に1本の髪なし～

I've not yet actually been able to make much sense out of the wiki for it yet, but it does user slayer cards for.. something.