I noticed that Necrotic Clutch is doing DOT to me as well as to the enemy. I don't see anything in the description explaining this. Is this normal?
It's normal. The tooltip reads thus: Grasps your opponent in a deathly clutch, dealing multiple waves of damage over 60 seconds. The first wave deals ____ to ____ damage, increasing to ____ to ____ damage for the last wave. Deals ____ to ____ damage over 60 seconds to you. Damage over time abilities cast while Necrotic Clutch is active are increased in potency. It's an additional kickback for a very powerful ability, which I find more interesting than simply boosting its mana cost, adding a cooldown, or a longer cast time. (The direct damage counterpart, Ghastly Revenge, increases energy costs by 5% while it's active.) It's actually useful in some situations -- it's very minor damage, but the very fact that it deals -some- damage allows it to break Mezzes cast on you. Certain mobs cast mezzes on their off-targets, so in the situation where your pet is maintaining aggro and you suddenly get mezzed out of the blue, you can break it thanks to Necrotic Clutch.