Six mana to destroy two creatures seems reasonable in black. Good; but not unreasonably so.
But I agree it's very fiddly, and likely to lead to.
"My turn? Cast this, end turn, cast this as well. Get the first one again. Your turn? Cast this. End? Ok, I get a copy of that other one frmo back then, and this one; I think? Abnd which of yours go off now?"
Very fiddly, and seems likely to encourage pure-blue-boring play.
Hmm, given it sets you to a fixed number, it's quite hard to abuse the infinite activations you get without it. you'd need a freidnly opponent also running a copy to go infinite.
"If... would... (instead)" denotes a replacement effect. Here this wording seemingly would replace it being blocked by having it gain trample. Doesn't seem right. Triggered is probably what you want.
> Whenever ~ becomes blocked by one or more green creatures, ~ gains trample UEOT.
Is it intended that you can't choose new targets for the copy in that it targets the same stuff as the original copy? If it is, then I would give it a reminder text regarding that. If not, then this makes Dualcaster Mage sad.
Oop. Yes, I was presuming two copies of Rise to the Challenge, and failed to mention it. And yes, Rise to the Challenge can't uptap the creature it's enchanting. I failed to read your card correctly also Sorrow.
@Vitenka. Control Magic doesn't work, because the Rise to the Challenge would fall off, since this is no long a legal target to enchant.
So I guess the card isn't borken with combos after all. The closest infinite combo I could get included Patron of the Orochi and Shifting Skies... oh hold it, that doesn't work either because the Orochi has a 'once only' clause. If a player can pull infinite with this card, they deserve a trophy. I'd suggest increasing the payoff.
Running a second copy of Rise to the Challenge would enable an infinite combo. There are a few infinite combos that could come up in limited which would be a problem.
See also Betrayal, which, yeah... it gets there with combos.
Still maybe potentially weaker than it needs to be. But it's tough to figure out how you make this better without getting crazy. Even if you just added "and gain 1 life." to the card, it becomes a two-card infinite life combo with Kor Line-Slinger/Minister of Impediments.
Draw two for 2 and at instant speed? This is crazy good.
Resonance mechanic seems quite pointless. I hardly see a scenario where you might want to cast one after you had cast another spell. So it seems like the condition would always be met and there's no real choice involved at all. Just "cast these spells first".
Delayed copy trigger is an annoyance which is easily missed (noticed it after reading the mechanic 3 or 4 times over). It also opens a pathway to minor memory issues where players just might forget about if a lot of others things happen on that same turn.
Six mana to destroy two creatures seems reasonable in black. Good; but not unreasonably so.
But I agree it's very fiddly, and likely to lead to.
"My turn? Cast this, end turn, cast this as well. Get the first one again. Your turn? Cast this. End? Ok, I get a copy of that other one frmo back then, and this one; I think? Abnd which of yours go off now?"
Very fiddly, and seems likely to encourage pure-blue-boring play.
I would try to come up with suggestions, but I don't know what's the flavor supposed to be about or what purpose the mechanic would fill.
Re: Resonance. Later that end step you can cast more spells though? I have trouble imagining the timing on this one.
Hmm, given it sets you to a fixed number, it's quite hard to abuse the infinite activations you get without it. you'd need a freidnly opponent also running a copy to go infinite.
If the choice is truely random, why is it important who makes it?
This is not an effect for a common. See this gatherer search.
What's up with the "at least two cards in hand" requirement? I don't get the reason behind it.
EDIT: Nevermind, I got confused there for some reason.
"If... would... (instead)" denotes a replacement effect. Here this wording seemingly would replace it being blocked by having it gain trample. Doesn't seem right. Triggered is probably what you want.
> Whenever ~ becomes blocked by one or more green creatures, ~ gains trample UEOT.
Peccary subtype to Boar
Peccary subtype to Boar
Peccary to Boar subtype
Peccary to Boar
Gave more of a payoff.
Is it intended that you can't choose new targets for the copy in that it targets the same stuff as the original copy? If it is, then I would give it a reminder text regarding that. If not, then this makes Dualcaster Mage sad.
Oop. Yes, I was presuming two copies of Rise to the Challenge, and failed to mention it. And yes, Rise to the Challenge can't uptap the creature it's enchanting. I failed to read your card correctly also Sorrow.
@Vitenka. Control Magic doesn't work, because the Rise to the Challenge would fall off, since this is no long a legal target to enchant.
So I guess the card isn't borken with combos after all. The closest infinite combo I could get included Patron of the Orochi and Shifting Skies... oh hold it, that doesn't work either because the Orochi has a 'once only' clause. If a player can pull infinite with this card, they deserve a trophy. I'd suggest increasing the payoff.
Oh snap, I didn't even read my own card.
No, you'd also need a Control Magic to actually go infinite, since you can't enchant your own creature with this.
So yeah; this is safe - which makes it kinda dull. But there's a few things it goes with, so it's not completely without use.
Just... 99% of decks would rather run an o-ring instead.
Running a second copy of Rise to the Challenge would enable an infinite combo. There are a few infinite combos that could come up in limited which would be a problem.
Can you explain during what part of the infinite combo the enchanted creature untaps?
See also Betrayal, which, yeah... it gets there with combos.
Still maybe potentially weaker than it needs to be. But it's tough to figure out how you make this better without getting crazy. Even if you just added "and gain 1 life." to the card, it becomes a two-card infinite life combo with Kor Line-Slinger/Minister of Impediments.
It's certainly not great. Combo enabling, though.
IMO this would be very weak powerwise even if it cantripped.
increased power to 1
Draw two for 2 and at instant speed? This is crazy good.
Resonance mechanic seems quite pointless. I hardly see a scenario where you might want to cast one after you had cast another spell. So it seems like the condition would always be met and there's no real choice involved at all. Just "cast these spells first".
Delayed copy trigger is an annoyance which is easily missed (noticed it after reading the mechanic 3 or 4 times over). It also opens a pathway to minor memory issues where players just might forget about if a lot of others things happen on that same turn.
I would assume that this is useless 95% of the time at least.
Hilariously overcosted. See Foul-Tongue Shriek.
This is pretty meh as a bad Mind Spring, but good as an uncommon - though that Unified Plans is much better.
Dropping Concentrate to a common could mess up limited pretty bad.
Reduced cost from
to 
