I'm going to assume your Saga is a standard 1, 2, 3. Since you didn't put anything else. That last ability is far too powerful as Dumplings said. Without restricting it in any way this has to cost a minimum of 2 more and possibly even more than that. If you limit what it can grab so nothing dangerous occurs then the cost could stay the same. As for wording. You just put the aura into play. The rules already do the rest by design.
The buff is small enough for an extra ability but without knowledge of entangler and how prevelant it would be its hard to say how good it is.