This item will aggro mobs within a 40 yard radius, including guards, so be careful.
It does not tap the mobs it pulls, and it generates very little threat.
It is useful for grinding, gathering quest mobs, and picking up entire rooms in Challenge Modes.
An extremely useful item for farming monsters despite the two-minute cool-down. I love the sound effect it uses, too.
Edit: It also greatly helps with earning Yak Attack.