Why entropy? Is this too make it less powerfull (as a mono) or just to make lycnathrope/werewolf easier to balance in a deck? I assume they would not stack, (due to the activation required) and due to the risk of EA, is this a correct assumption?
I picked entropy since I wanted an element of chance in the drain level. It also does help in balancing since the ability, on average deals a significant amount of drain compared to other CC effects (5 unupped and 5.5 upped)
The permanent does not stack, although you could certainly use more than one on the same target in a given turn.
Thematically, I think that reflective shield should not reflect this effect since it does not reflect shard of void... On the other hand, it would help make reflective shield more valuable if it did... I could go either way really.