Mobs - elBukkit/MagicArenas GitHub Wiki
Mob Arenas
Mob arenas are a work-in-progress feature of MagicArenas, but they are functional in the latest dev builds. They can be used to spawn Magic (or vanilla) mobs into an arena to give the combatants some extra challenge.
Example of setting up a simple mob arena:
# Add spawn locations for mobs to appear:
/arena configure spleef add mob_spawn
# Choose the types of mobs to spawn:
/arena configure spleef add mob warlock
It may make sense to allow only one player in a mob arena, by default an area requires 2 or more players, you can change that like so /arena configure spleef min 1