I think technically yes. They moved from activated abilities to mana costs in Modern Horizons without having to change anything

Spells costing just energy is a thing they avoided doing first time around. It's certainly a place to stretch into - but the problem with it is that this is a completely green spell. That can be cast in a pure-blue deck.

Maybe that's ok. Artifacts exist after all. It's just a thing to be careful about.

Interesting. Everybody would understand this, but I don't think it's technically covered by the rules.

Vitenka- You're absolutely right about it being pure green. I was only envisioning red-green because of the draft archetype in Kaladesh. I definitely did not consider that other colors could play this if they built energy decks.

Huh. I mean, this is a pure-energy spell. That you can make counterspell-proof if you're feeling mana rich.

One complaint I guess I'd raise - what identity do you want to give to energy-colour spells? Devoid had its own theme, energy would need one. Does "Get big and fight" fit that theme?

I think, I'd like these to be like hybrid mana or phyrexian mana, where you just get a discount for energy. Doesn't undermine the resource foundation of the game that way.

@SecretInfiltrator- but the whole point of the card is that Monster Energy turns your creature into a Kyle, ready to bust drywall.

I don't see how the ability to pay mana or having a converted mana cost undermines that.

The key of this card's existence is energy should be spent to cast it, not mana. A colorless zero could sit in the top right corner with the first bit of text being "As an additional cost to cast ~, pay ." ­
More formal, less fun appearance, but mostly the same result in the long run, sans interactions caring about mana value.

Yet you essentially give it a kicker mana cost, so I fail to see that "not spending mana on this" is actually all that much of its energy.

What's up with that? An artificially inflated converted mana cost is preferable to an actual mana value how?

And then there is the fact that a hybrid energy/mana cost could still be paid with only energy, so you are not losing the option to cast it without mana.

None of this touches the "busting through drywall" aspect of the card as far as I can tell.

Trample is how the creature bursts through the drywall.

For the mana kicker, that was me associating the card with a draft archetype. I mean, I'd honestly be fine omitting that feature.

When you drink a Monster Energy, why would that be mana and not just Energy?

When you eat Food, why would that cost mana and not just Food.

But now also remember that I still suggest a design that can be paid purely with energy. My suggestion is that you could allow mana to be spend to make up for missing energy. And that conversion of mana to pay for an energy cost would be just the same as using mana to produce energy with Glimmer of Genius and then using it to pay for the energy cost.

Or where do you expect the to pay for that cost to come from?

So my suggestion to have e. g. a (/)(/)(/)(/) cost would

• Allow you to associate the card with colors and a draft archetype without the first ability because you actually have mana in the mana cost.
• Which also automatically means there is a mana value that you don't have to define in the rules text.
• Allow you to still pay the card purely with if so desired.
• Not touch the second ability unless you decided to adjust e. g. the p/t bonus for balance. So trample is still there.

It would not be much different from costing and having "As you cast this spell you may pay up to twice. Each time you do, gain . You must spend this energy to cast this spell." It's just like paying whatever currency you use to get yourself a can of Monster Energy anyway. And I assume in MtG that currency was mana.

I see your viewpoint, however I am still absolutely against. I'd rather have the card not be cast or even exist than possibly be cast directly with mana (with the exception of any cards creating hoops that might exist [none of which I know offhand]).