Skull shield buff sounds as another quintessence nerf
I know that this buff would give it more power(and it was needing it) but prefer so much the light version buff.
I think skull shield should have a buff like 'For every point of damage 50%chance of putting a skeleton out' or 'For every point of damage reduced inflict 1 damage to the enemy'.
An ability like those mentioned before should make skull shield a good choice with aflatoxin!
Undead passive ability is cool but I find it a bit overpowered; Reverse Time makes a skeleton an average of 3,34|4,12 creature probably with a good ability.
Also I'd find odd seeing a killed virus making a skeleton(if boneyard in play) that once reversed became a purple dragon
However other updates are great! 8)