This idea came to me while I was reading about the swarm.
This arena will be greatly based on micro management and the equipment that you have. In the arena, you will be placed under a eternal curse. This arena maybe PVP or PVE, haven't decided. Re-equipping will be allowed in the arenas. The point of this place is to pick the right loadout to kill your enemy without losing too many hearts and to profit from the hearts that your enemy drops. This maybe a little confusing so I will draw it out:
I use a weapon to kill a guy and the curse makes me lose 10 hearts, the enemy drops 7 hearts = BAD
I use a pierce and put on pierce armor and I only lose 5 hearts this time, enemy drops 7 hearts = GOOD
Properties of the curse will most likely have to be modified. It may also be best if the player chooses from an arena provided arsenal. This idea needs refining so I am very open to modifications, ideas, criticism, etc.
What about lockdown with just vials?