How to make a mob attack a mob [duplicate]

First, summon the target mob with determined a UUIDLeast and UUIDMost. For example:

/summon Wolf ~ ~ ~ {UUIDLeast:0L,UUIDMost:0L}

Then, simulate the target mob hitting the attacker mob with a snowball to make the attacker angry, like this:

/execute @e[type=Creeper] ~ ~ ~ /summon Snowball ~ ~2.8 ~ {ownerName:"0-0-0-0-0"}

(OwnerName needs to be the UUID of the entity summoned in the first stage.)

the way i would do it would be i would make a villager on team 1 and another on team 2. then make 2 zombies and one on team 1 and another on team 2. then i would set friendly fire off for both the teams. now make the villagers invisible. then if they get close enought they will attack each other. this wont make them kill each other. but they attack each other. then to make them kill each other you could make it detect if the villager died, and if it did its team mate would be killed. im sorry but i cant simplify my explanations that well. i always make my things too complicated