This is the Titan Mob Arena.

It allows you to choose types of mobs to spawn, and then spawn them. You cannot leave the arena until all the mobs are dead, or you are.

If you die, the mobs left will prevent you from returning, forcing you to loose all your armour/weapons. You may only join the arena at the beginning and end of a round.

This is a great pvp practice area, or an area to gather resources from mobs.

If you wish to see it in action,

A) Download it here!
B) get onto titankingdoms.com (server IP) and see for yourself!