Haven't really developed the idea that much so don't kill me straight away but here goes...
fyi i do realise some champions like rengo and twich would most likely be too strong here and will have to be disabled for the gamemode or something idk.
I have thought of 2 options for the gamemode and other ideas are welcome cos im not so smart ;) .
Basically one way or another the point is to get the enemy team's fountain (where there's aportal as mention later), whether through brute force or stealth. Most likely there will be no normal towers and just a map filled with jungle, frequently spawning monster camps and bushes - possible even a lane/s too. By getting gold through kills and monster camps you will be able to buy placeable defenses like mini tesla towers or something, traps, vision wards and maybe even pets that act as sentries/wards. On the other hand you will also be able to buy mostly sneaky and some offensive items or whatever they will be. For example invisibility actives, trap disablers, maybe placeable walls or bushes to deny vision in that sense, who knows!
Some interesting features can be included - for example: maybe the river could give vision to anyone/thing on it and u might have to buy something in the shop to "build a bridge " across it which wont reveal you if used. OR... the opposite maybe vision will be reduced while walking through because of the mist and wards wont work there. Maybe you will be able to turn the summoners rift into night time kind of like a longer but less impactful nocturne ult. Maybe even you could spawn natural disasters like a tsunami to knock players back very far... (just a random idea)?
1st option: try get your whole team into the enemy team's portal at least once (in enemy fountain) to win
2nd option: get to the enemy team's portal to recieve an insane buff to be able to kill people easier to win more points - with a point system kind of like hunt of the blood moon - kills (and possibly secondary objectives) = points.
Anyway let me know what you think and i can edit this as i get feedback or i can completely scrap the idea and call it **.
Thanks for reading this far if you made it!