creep control - attack commands

The basis of my map is an AOS-style battle, with creeps spawning for either side and attacking each other. Now this works fine, but every now and then I spawn a large creep with them - but for some reason this creep keeps running back to the spawn point after it fights a group of enemies. What would cause this to happen?

You are forgetting that what you are spawning is a creep. You need to go into gameplay constants and mess with the creep constants. Guard Distance, Return Distance, return time, etc. There is another problem with creating creeps for spawns in an aos, creeps tend to run from a fight with a unit that is considered a building(From my observations, they run at half health). Now, I fixed that by simply making the towers be not considered a building(a simple change to false in the map editor), but now, although the creep itself responds as I wanted it to, the building can be walked through, even though ai placement radius and collision values are nowhere near zero. Good luck.

It is not controlled by any trigger, AI, or command. Therefor, since it has no player to give it orders, no triggers to give him commands, and no artificla intelligence to do certain things, it'll act like a Melee creep.

If you've never played melee, that's... 'guard a certain spot, get angry if attacked or enemies are too close, attack, and either return to guard spot after defeating all enemies, or chasing them to a certain distance'.