I feel like the damage share ability some of the void creatures have may be a bit overtuned.
For the player, once you realize what's going on, it's not that bad. You can just stay out of range of the thing and you're fine. Or, if you're in range, you can just hold fire for a bit if you need to.
Unfortunately, these simple tactics are not things the AI is capable of doing, and every two or three fights I'll lose an otherwise-highly-durable ship to this ability, since it completely ignores shields and tends to deal very high damage. (Significantly higher than how much the voidling takes, even; I've seen the retributive system kill capital ships from damage that the destroyer-class voidling survived.)
And it just feels cheap when this happens.
Now, I'll give you: this is definitely a neat idea. But I think it'd work better as something similar to, say, the Master of Orion II energy absorber, where the retaliatory strike comes in the form of a regular projectile attack rather than the current instant unblockable death.