The Mob Battle Mod introduces a series of wands that enable you to take control over who or what a mob attacks. The Enrager is the main wand that you simply click who want to do the attacking and then click the next mob for it to attack.
You can use the multi-enrager to do the same thing except it allows multiple mobs to gang up on just one mob.
If you want to heal a mob then use the Mob Healer Wand and click the mob you want to heal.
The Armor Editor allows you to customize what armor a mob can wear or even just remove existing armor altogether.
And if things seem to be getting out of hand you can always use the Mob Killer to end it all in one click.