I don't play MTG but I think if I were to design a card for it based on myself it'd have an ability that's along the lines of:
Once per round, prevent an opponent from casting a spell. When this ability is used, [Entropy] restores 1 health per mana the spell cost, up to its maximum. The spell and the mana it would have cost are discarded.
not sure what the health or damage would be though
maybe it's one of those funky reversible ones. like the 'normal' state (what it starts as) has that ability, and then a condition that makes it flip if it eats enough spells.
something like this:
Entropy, Arcane Devourer
(see above). When Entropy, Arcane Devourer consumes a spell, add a token. When the number of tokens on this card reaches 10, transform into Entropy, Prime Earth Elemental and remove all tokens.
Entropy, Prime Earth Elemental
Spells do not affect this card. If brought to 0 health, transform into Entropy, Arcane Devourer.
When attacking with this card, roll a 6-sided die. If it lands on 6, create a forest. If it lands on 5, create a mountain.
