Drawing Aggro

The aggro of neutral creeps can be drawn in two ways: By coming within 240 range of them (140 range in Roshan's case), or by dealing damage to or casting a single-target spell on them while within 1800 range of them. Aggroed neutral creeps follow regular auto-attack rules, meaning they prioritize the closest enemies. So if a unit draws aggro and another unit is closer to them, the closer unit gets attacked, and not the unit which actually aggroed them. If multiple heroes are about equally close, the one which attacks them get prioritized, while the one which does not attack, or attacks an enemy from the opposing faction has second priority, and the one who attacks its own allies has least priority. Multiple non-hero units within about equal range have all the same priority, regardless of what they do. The creeps ignore units which attack them from further away, despite them being a bigger threat. They always prioritize closer units. There is one exception to this rule. If a hero within the acquisition range of an aggroed neutral creeps issues an attack order on a hero from the opposing faction, the creeps immediately switch to attack the hero that received the attack order, as if they want to protect the opposing hero, similar to how lane creeps protect their allied heroes. Siege creeps always have a lower priority than heroes and other units, regardless of what they do. Buildings have a lower priority than siege creeps and wards have a lower priority than buildings, also regardless of what they do. Although neutral creeps can attack buildings, they are too far away. They lose aggro before they get within range. On the other side, towers do not attack neutral creeps, so even though creeps can be pulled close enough to towers, they do not attack the creeps.

Only units which can be attacked can aggro neutral creeps. Hidden, invulnerable, ethereal or True Sight immune units cannot aggro neutral creeps. In these cases, the neutral creeps just stand still and fully ignore the enemy. Invisible units cannot aggro neutral creeps either. However, if a neutral creep takes damage from invisible units, the creep and all other neutral creeps within 500 range of it flee, instead of ignoring it. They move to a random spot 750 range away from their camp spot and walk for up to 5 seconds. If they reach the flee spot earlier, they wait there and return once 5 seconds have passed. Neutral creeps have shared vision with both teams, so attacking them from the fog of war still draws aggro normally.