WotLK Patch 3.3.3 (2010-03-23):
In addition to its previous effects, this talent now also prevents diseases from being dispelled from victims afflicted by Unholy Blight.
WotLK Patch 3.3.0 (2009-12-08): This talent now deals only 10% of Death Coil damage as a damage-over-time effect on the target.
WotLK Patch 3.2.0 (2009-08-04):
This talent has been redesigned. It no longer deals damage to nearby targets. Instead, when you deal damage with Death Coil, the target will take periodic damage for 10 seconds equal to 20% of the damage done by Death Coil. This damage accumulates in the same way as [Ignite] and [Deep Wounds].
WotLK Patch 3.1.0 (2009-04-14): Have swapped places with Gargoyle in the Unholy tree. Gargoyle is the new Unholy 51 talent.
WotLK Patch 3.0.8 (2009-01-20): Cost reduced from 60 to 40 runic power