... That tells me if my current mob has the mangle debuff.
When raiding with multiple feral druids, mobs tend to have a crap-ton of debuffs on them, and the mangle debuff may be lost in it all. In order to maximize my DPS (when I dps, which is only about 1/3 of the time, but w/e) I don't want to be mangle-ing when I don't need to.