The Harrowing, The underworld, The league.

Hey Riot and summoners. Just throwing a thought out there. With one of the seasonal events coming around soon, I'm just wondering - any ideas on what the harrowing will pertain this year? I'm excited to buy me some Underworld Wukong, but a thought came across my mind. Last year we had the slayers and zombies. Will this year feature some underworld/haunted skins again? The underworld skins have a eerie yet interesting and cool theme, with the green, greys and blues, and I'd love to see the newest creation for them. Any information on this?

And to my summoners, what do you all think? Any ideas or hopes for the underworld/haunted/zombie/slayer skins? Would love to hear about it!