What does tethering to enemies do?

I found an item with the following attribute:

Chance to tether yourself to an enemy.

When I get shooting at people, sometimes I can see this in action. I see a green beam form between myself and the enemy. As far as I can work out though, that's the extent of this feature. It doesn't appear to restrict movement of either party, and if I move far enough away or kill the tethered enemy, it disappears.

Does it do anything useful?

Solution 1:

It hurts the tethered enemy for 60% of your damage per second.

I think that also applies to all enemies touched by the tether, but I'm not 100% about that.