Comment about the old version
Note: This is upgraded cards. Remember that hidden upgrade cost reduction per card.
Lava Destroyer (7|1 for 5
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+ 1 card)
+Growth (9|3 for 5
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+ 1
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+ 1 card)
+Nature's Harmony
9 attack increases to 15 attack
9attack -> 15 attack = +6 attack
9|1 +6|+6 -> 15|7 for 5
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+ 1
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+ 2
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+ 2 cards
Ruby Dragon (15|2 for 12
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+ 1 card)
Note: Unupped cards
Cockatrice (4|4 for 3
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+ 1 card)
+Nature's Harmony
4 attack increases to 8 attack
4attack -> 8 attack = +4 attack
4|4 +4|+4 -> 8|8 for 7
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+ 2 cards
+Adrenaline (17 damage per turn|8hp for 11
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+ 3 cards
Adrenal Horned Frog (12 damage per turn|3hp for 6
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+ 2 cards)
Comment about the new version:
3, 8, 15
-5, 6-11, 12+
So it
Reduces the attack of any creature with more than 15 attack to 15 (until regained by the growth mechanism that all have except chimera)
Reduces 9-11 attack by -1|-1 to -3|-3
Reduces 4-5 attack by -1|-1 to -2|-2
Never buffs more than +3|+3
I think the old version was more useful. The new version is only useful as CC. (not very useful at that either)