Judgement has been made.
Fledgling Stonehowler 1RG
Creature - Beast (U)
3RG: Monstrosity 1.
When Fledgling Stonehowler becomes monstrous, put three +1/+1 counters on target noncreature land you control. It becomes a 0/0 Elemental creature with haste that's still a land.
3/3
Design
(2/3) Appeal - Timmy likes the big numbers (and cats.) Spike likes the strictly better Watchwolf.
(3/3) Elegance - It's very elegant and easily grokkable. The name sounds like it would fit in well in Theros, but it's still generic enough to show up in other environments as well.
Development
(3/3) Viability - No color pie breaks. It's a little pushed for an uncommon, but the abilities can exist at uncommon, the numbers just need tweaking.
(2/3) Balance - A quick Gatherer search reveals there is no 3/3 for 2 mana with a strict upside at uncommon, and only two with no upside or downside (Watchwolf and Kalonian Tusker.) The closest I can find would be Zhur-Taa Goblin, which is basically just a 3/3 that has the option of being a 2/2 with haste, so you're still not getting a 3/3 with upside for 2 mana. It would be fine at rare at its current rate (if unexciting,) but the numbers would have to be adjusted (though not by much) to have it fall higher on the curve for it to be an uncommon with its current abilities. I don't think Watchwolf can be fully obsoleted at uncommon just yet.
Creativity
(1/3) Uniqueness - It's Watchwolf that becomes bigger Watchwolf. There are multiple creatures that gain keyword abilities when mostrous, so the concept is hardly new.
(2/3) Flavor - The flavor is fine, especially for a Theros setting, but without art or flavor text, there's nothing really pushing it over the top flavor-wise.
Polish
(3/3) Quality - No issues.
(2/2) Main Challenge - The challenge was met.
(2/2) Subchallenges - It's multicolor and it's an uncommon.
Total: 20/25
Design
(1/3) Appeal - I'm having a hard time determining who this appeals to. I feel that it's not flashy enough to appeal to Timmy, not enough combo potential to appeal to Johnny, and not a good enough rate to appeal to Spike. But it is very flavorful, so it's at least appealing to Vorthos.
(2/3) Elegance - The card is easy to understand and make sense flavorfully. However, when combining two mechanics like this, it's nice to see the two mechanics interact with each other in a new way, and unfortunately there's no real interaction between Monstrosity and Mutate--there's no "greater than the sum of its parts" feeling.
Development
(3/3) Viability - Mechanically, this just mono red, but flavor lets it dip into green. It's definitely not too powerful to be an uncommon.
(2/3) Balance - This kinda feels a little underwhelming for an uncommon. I think it could be pushed a little, but I'm not sure where without making it too good. My initial inclination would be to have the damage scale based on the creature's power, which would also give it some interaction with Monstrosity, but the numbers would probably have to be tweaked a little to account for that. Then again, current mutate creatures can do some ridiculous stuff when you start mutating several creatures together, so maybe that's just to be expected with that mechanic.
Creativity
(2/3) Uniqueness - It combines two abilities that have never been on a card together. Unfortunately, Monstrosity and Mutate don't really intersect mechanically to make something new.
(3/3) Flavor - They do, however, intersect very flavorfully. I would love to see the art of this writhing, monstrous mass of tendrils and vines.
Polish
(2/3) Quality - You're missing a ":" and a space between the activation cost and Monstrosity 1. Also, I believe it should read "Whenever this creature mutates or becomes monstrous" to stay in line with the existing mutate template.
(1.5/2) Main Challenge - It meets the conditions, but it doesn't feel like Monstrosity is the focal point of the card; it feels like an afterthought. It feels like a Mutate card with Monstrosity tacked on. I wish the Monstrosity effect were bigger than the Mutate effect, or at least had a more significant impact, as Monstrosity is a one-time thing, while the Mutate trigger can happen multiple times in a game.
(2/2) Subchallenges - It's multicolor and it's an uncommon.
Total: 18.5/25
Design
(1/3) Appeal - There's really not much combo potential for Johnny, and the rate isn't good enough for Spike. The effect isn't really all that flashy, but I can see a Timmy out there stoked to put this in their RW Cyclops deck.
(2/3) Elegance - It all makes sense, though I'm a little dubious of the flavor, especially in the context of the mechanics (more on this later.)
Development
(3/3) Viability - Fits snuggly in the RW portion of the color pie. The mechanics are appropriate for an uncommon.
(2/3) Balance - I can't imagine the opponent ever paying the tribute, unless they have a creature or planeswalker that 1 damage will kill. The problem with most Tribute cards is either that both modes are underwhelming, which is compounded when you don't even get to choose which mode you get, or there's a very obviously better mode, and so the tension isn't there in the decision making. I feel like this falls into the latter category, as 1 damage is rarely comparable to a +1/+1 counter.
Creativity
(1/3) Uniqueness - Tribute already explored the space of "etb effect vs making your creature bigger." I don't really see anything here that sparks newness.
(1/3) Flavor - I don't really get a lot of flavor from this at all. I don't know why the cyclops has lifelink, or why it's dealing a damage a damage for not receiving tribute. Being battle-scarred doesn't really explain either of those. As a cyclops soldier, I'm imagining him in the Boros Legion, which makes the tribute seem confusing as well. All in all, I see a lot of mechanics that work well together mechanically, but just don't tell a cohesive story whatsoever.
Polish
(3/3) Quality - No issues.
(2/2) Main Challenge - The challenge was met.
(2/2) Subchallenges - It's multicolor and it's an uncommon.
Total: 17/25
Design
(2/3) Appeal - Timmy likes the splashiness of the effect. While I doubt this would be constructed viable, this is a limited bomb which certainly appeals to Spike.
(3/3) Elegance - It's a 3/3 with Monstrosity 3 that deals 3 damage to other creatures. Very satisfying. The flavor and the mechanics mesh nicely.
Development
(2.5/3) Viability - I don't really see any color pie issues, though I question why this is green. Green adds nothing to the design. Generally when we see multicolored cards that could be monocolored, the color identity ties into the flavor of the card somehow, which I don't really see here. It could maybe serve the greater flavor of the set, but there's not enough here to make that determination. Other than that, everything about it is appropriate for an uncommon.
(2.5/3) Balance - This card is pretty pushed from a limited perspective. A 3/3 trampler that pings all other creatures for 4 mana is already a pretty good rate for an uncommon. The Monstrosity cost, which you can pay immediately after untapping, turns this into a significant threat and packs more removal. I guess the second color could almost be considered a drawback to keep it in check in limited, but still, I would consider first picking this every time. Despite its power level in limited, I don't see it warping any constructed formats.
Creativity
(1.5/3) Uniqueness - It's not particularly unique. Monstrosity led with the concept of "triggered ability when this becomes monstrous" and the trigger isn't especially unique.
(3/3) Flavor - The flavor is pretty spot on, and a rare example where I don't think the flavor could necessarily be improved with flavor text.
Polish
(3/3) Quality - No issues.
(2/2) Main Challenge - The challenge was met.
(2/2) Subchallenges - It's multicolor and it's an uncommon.
Total: 21.5/25
Design
(1/3) Appeal - This is made for Johnny, between the free sacrifice outlet and the replacing of +1/+1 counters to build your own repeatable gravedigger.
(2/3) Elegance - It took a second for the mechanics and the flavor to click for me, but afterward it made a lot more sense.
Development
(0/3) Viability - I would avoid having this remove +1/+1 counters, purely for memory reasons. A creature can only become monstrous once, and the +1/+1 counters generally serve as a reminder of which creatures have become monstrous. As is, I don't believe this would be printed, and I don't believe if Monstrous were ever revisited that they would explore with removing +1/+1 counters. Furthermore, uncommons typically don't have this level of recurring card advantage, even if you do have to jump through a hoop.
(2/3) Balance - On the surface, it looks as if you're trading creatures one for one between your battlefield and your graveyard. However, if there are methods of replacing the +1/+1 counters on this guys, this turns into a pretty significant draw engine. Not that that in and of itself is busted, but how easy it is to pull that off is certainly something to consider when crafting a Standard and Limited environment.
Creativity
(3/3) Uniqueness - Memory issues aside, it's a unique take on Monstrosity.
(2/3) Flavor - The name is a little generic, even if it is a pun. Some flavor text would be really nice for this card. But overall the flavor is there.
Polish
(2.75/3) Quality - You're missing a period after "Monstrosity X" but otherwise, no issues.
(2/2) Main Challenge - The challenge was met.
(2/2) Subchallenges - It's multicolor and it's an uncommon.
Total: 16.75/25
Design
(2/3) Appeal - Spike is all about a 3/3 flier for 1 mana. I feel like some Johnny brewer out there would come up with some way to abuse repeatedly exiling a spell from hand, but it's just not me.
(3/3) Elegance - Everything ties together quite nicely. It's easy to read and easy to grok.
Development
(3/3) Viability - Blue and Red have an overlapping interest in instants and sorceries, so no color pie breaks. The mechanics are appropriate for an uncommon.
(2.5/3) Balance - Depending on the format, this could potentially be a constructed all star. It's definitely more powerful in constructed than in limited due to the predominance of creatures in limited. I'm guessing this would fall around Delver of Secret's power level, which is fine, but the format crafted around it would need to be wary of any hyper efficient spells that would support this kind of aggressive strategy. We don't want UW Delver in Standard all over again.
Creativity
(2.5/3) Uniqueness - Non-mana costs for Monstrous is new. It does some things new, but it's still just a very aggressively cost beater.
(2.5/3) Flavor - I like the flavor quite a lot, feeding a spell to your guy to make him more powerful. Some nice flavor text, which there should be room for, would really make this sing.
Polish
(3/3) Quality - No issues.
(2/2) Main Challenge - The challenge was met.
(2/2) Subchallenges - It's multicolor and it's an uncommon.
Total: 22.5/25
Design
(1/3) Appeal - Giving stuff to your opponent is right up Johnny's alley.
(2.5/3) Elegance - The card as a whole makes a lot of sense. Flash feels out of place though, especially since it feels like you would be getting a 5/5 much less often than the opponent would be getting a 3/3.
Development
(2/3) Viability - I'm torn on whether UB should ever have a 5/5 for 3 mana, even if the opponent decides whether or not you have it. The complexity of this card feels appropriate for rare.
(2/3) Balance - Punisher cards are tricky to balance, as you have to create enough tension between both modes where it's not an obvious decision that the same mode should be chosen each time. I feel like this is a little more skewed to not paying the tribute, as a 5/5 for 3 is a very good rate and a much faster clock than the 2 damage per turn it would otherwise provide the opponent, not to mention the added benefit of the opponent just getting a free 3/3.
Creativity
(2/3) Uniqueness - This is a nice little twist on Sleeper Agent, but it's not doing much new.
(2/3) Flavor - The flavor is nice, though the name is a bit generic. Some flavor text would really help in this area to tie everything together.
Polish
(3/3) Quality - No issues.
(2/2) Main Challenge - The challenge was met.
(1/2) Subchallenges - It's multicolor but it's not an uncommon.
Total: 17.5/25
Feyd_Ruin - 22.5
ECPmath - 21.5
RaikouRider - 20
Jimmy Groove - 18.5
Henlock - 17.5
kwanyeegor-ii - 17
Krypster - 16.75