You've still not fully answered where the -1's will stop for the sapling will it eventually heal your opponent or just stop?
I'd probably go for it eventually dealing negative damage, therefore making it more risky to play and hence less usable in certain cases.
Yes I did
So just to be clear, yes, Sapling would eventually start healing your opponent.
Hm...I fully endorse this card, now that I think about it. I just thought about a few other scenarios for these occasions.
If someone played a Gravity shield on Sapling, it'd actually negate the negative damage/healing component it'll reach after having it on the field for an extensive period of time, whereas on the Elder Tree, after two rounds, it'll start doing VERY noticeable damage (not equivalent to a dragon per say, but enough to make the opponent either want to eat it up with an Otyugh, or hit with a Lightning Bolt to kill it before it starts hitting hard). If you get this as part of a mutation/improvement on a creature with extremely low attack and high hit points, then it becomes
extremely detrimental to the person who has it (which is nice, considering how the Fallen Druid can sometimes screw us over in terms of getting something we really need).
Another scenario I thought about was having this in a rainbow deck with Eternity - if you rewind it at the right point (for either tree), you can prevent the death/healing components of either card, and playing it out again to do wonderful damage (assuming you're not facing against horrid crowd control).
Oh, and plus the other additions of Chaos Power, Blessing, Rage Potion, Adrenaline,
Liquid Shadow (that would change the effect of the two cards, won't they?),
and even throwing a Quintessence on them (think of THAT!
An offensive use for the tree that heals you continually that can't otherwise be removed?)...
...oh man, too many ideas for a card like this. It's a real gamble for Life, but I love it!