So i recently noded ineu valley 2 and was playing around with a swarm of antlions in the antlion cave pit. I realized that holy shit that was fun so i was thinking i should make a map dedicated to npc battles with automated spawn systems in place. 
This map would have a lobby with teleporters to each arena. But i dont know what to make for them. I want to have 6 different arenas 
The first will be an antlion cave pit like in ineu valley 2. What should i do for the other 5?
Arenas-Antlion Caves 
REF-Apocalypse City Intersection 
REF-Temple 
REF-Lava 
REF-Forest 
REF-Office 
REF