Blightshadow Scorge, a new scout prestige AA, has an incredibly low hit rate. The issue is that it's a spell, rather than a combat art. This is a scout only AA, and scouts (other than bards) don't have spell skills (disruption for this one) as a base skill. Because it's not a base skill for the class, we can't even increase it through snacks or equipment. With 0 disruption, Blightshadow Scourge has about a 60-70% resist rate on orange con mobs, 50-60% resist rate on white to yellow con. It rarely hits, making it fairly useless, but this is one of the end line new AA's for scouts. Since it's a scout only AA, I assume the fact it was made a spell rather than a combat art is unintentional or a bug.
Liked the OP, and adding that for rogues, this ability is named Danse Macabre. The fighter abilities also fall under this issue for brawlers and warriors, since they do not have the disruption ability by default. (Clinch for brawlers)