One of my favorite ideas, though, is creatures that self-bounce like glitterfang. You can keep re-triggering the mutation abilities that way, since both the creature and the mutation will return to your hand.
In a similar vein, sticking them underneath manlands means you can keep them safe from sorcery-speed removal.
The original question asked, what happens if my Mutate target ceases to be a creature before the mutate spell resolves, is also answered in themechanics article:
if a mutating creature spell tries to resolve but can't because its target is illegal or has gone missing, the mutating creature spell will simply resolve and enter the battlefield.
The mutate spell has a target of a non-human creature you control. If you target Thassa and she stops being a creature before the spell resolves, your mutate spell enters as a creature, instead of mutating.
My biggest question is about the difference between mutating on top of an animated manaland vs. mutating underneath one.
Reading the mechanics article, it seems obvious that mutating underneath an animated manland means it stops being a creature at the end of the turn, and you can animate it again later to mutate it more. But if you mutate on top of the animated manland, does it stay a creature permanently?
Considering we'll be back in Zendikar soon, where a new set of manlands will surely appear, this is an important question to answer. It may not be answerable until the CR is updated for Ikoria, though.
Splintering Wind is a blast in my enrage deck. Every time I play the deck and make people afraid of what should be a legitimately bad card is a good game.
But 2G: ping a creature, make a flying blocker, then later trigger all of my enrage creatures and take a damage is so good in that deck.
The Jinxed Idol is still a card you own (Zedruu would be a bit useless otherwise, wouldn't she?), but since you no longer control it you cannot target it with Zedruu's activated ability.
Now, if that player is also enchanted with Paradox Haze and thus has another upkeep after the first one, and resolves Teferi's Protection during the first upkeep, I don't know. I think, that you can still choose that option and it will just fail to do anything, though.
If they have two upkeeps and resolve Teferi's Protection during the first one, they will not control Captive Audience during the second one (it'll be phased out) and they won't have to pick anything because nothing will trigger.
Closest card to winning would be the new 6 mana Chandra.
You could certainly resolve Awakened Inferno through this board, but her -3 doesn't kill anything (Meddling Mage is a 6/6 thanks to at minimum two Elesh Norns, on top of all of their permanents being indestructible), her -X can't even target anything thanks to Privileged Position (not to mention the board being indestructible), and while you can hand out emblems all day like candy, Platinum Angel means you can deal all the damage to them you like, they still won't die.
(And even without the Platinum Angel, they're dealing 2 damage/turn with Purphoros, making an additional Elesh Norn each turn, and can attack you, while you're waiting 6 turns to cast Chandra in the first place.)
Only the original Viper has Kusari-Gama. Only the original will be a 10/3, while the myriad copies will be 3/3s. Only the original will deal damage to other creatures defending player controls (assuming the player being attacked by the original blocks in the first place).
Is it possible to remove a chapter counter in response to the final trigger, to prevent it from being sacrificed. Example: The Birth of Meletis/Thrull Parasite?
Basalt Monolith with 2 additional mana from any source gives you infinite colorless mana; add Voltaic Key and you have infinite artifact untaps without needing a single artifact tapping for 4.
As a removal spell, Ceaseless Hunger is the clear winner; hits two targets instead of one, for one less mana, and exiles instead of destroys them.
As a permanent, Infinite Gyre is the winner, though the race is closer than comparing them as a removal spell; a single attack by either is usually not a game-ending threat, but letting either live for very long can end up a serious issue. Gyre becomes a problem much more quickly than Ceaseless Hunger, though.
As a card in the library, Ceaseless Hunger does absolutely nothing while Infinite Gyre can protect you from mill and can be involved in some combos (for example, Syr Konrad, the Grim+Basalt Monolith+Mesmeric Orb).
Golos, Tireless Pilgrim's activated ability exiles three cards and then gives you permission to play them from exile.
Exile is not your hand.
The mutate spell has a target of a non-human creature you control. If you target Thassa and she stops being a creature before the spell resolves, your mutate spell enters as a creature, instead of mutating.
Reading the mechanics article, it seems obvious that mutating underneath an animated manland means it stops being a creature at the end of the turn, and you can animate it again later to mutate it more. But if you mutate on top of the animated manland, does it stay a creature permanently?
Considering we'll be back in Zendikar soon, where a new set of manlands will surely appear, this is an important question to answer. It may not be answerable until the CR is updated for Ikoria, though.
But 2G: ping a creature, make a flying blocker, then later trigger all of my enrage creatures and take a damage is so good in that deck.
Every color has at least one card capable of tutoring for an arbitrary commander, as well: Thalia's Lancers, Long-Term Plans, Demonic Tutor, Gamble, Worldly Tutor. (Hell, with the exception of Worldly Tutor, those options can also all tutor planeswalker commanders.) For certain commanders, more tutor options are available (for example, Imperial Recruiter can get Kiki-jiki, Mirror Breaker, but not Lathliss, Dragon Queen).
(And even without the Platinum Angel, they're dealing 2 damage/turn with Purphoros, making an additional Elesh Norn each turn, and can attack you, while you're waiting 6 turns to cast Chandra in the first place.)
- Any lands that taps for 4+ mana with Deserted Temple gives you infinite land untaps. (Scorched Ruins can do that in any deck, and Nykthos, Shrine to Nyx can do it in any deck except colorless.)
- Any artifact that taps for 4+ mana with Voltaic Key gives you infinite artifact untaps. (Everflowing Chalice, Astral Cornucopia, and Doubling Cube can do that in any deck, and Nyx Lotus can do it in any deck except for colorless.)
- Basalt Monolith with 2 additional mana from any source gives you infinite colorless mana; add Voltaic Key and you have infinite artifact untaps without needing a single artifact tapping for 4.
Ashnod's Altar and Nim Deathmantle combo with a number of creatures in every color and in colorless to produce infinite colorless mana. In many cases, you also get infinite creature tokens or infinite damage/life loss to your opponents. A smaller set of creatures in every color (and colorless) can also use Phyrexian Altar instead of Ashnod's. Some example creatures include Evangel of Heliod, Master of Waves, Abhorrent Overlord, Chancellor of the Forge, Hornet Queen, and Myr Battlesphere.As a permanent, Infinite Gyre is the winner, though the race is closer than comparing them as a removal spell; a single attack by either is usually not a game-ending threat, but letting either live for very long can end up a serious issue. Gyre becomes a problem much more quickly than Ceaseless Hunger, though.
As a card in the library, Ceaseless Hunger does absolutely nothing while Infinite Gyre can protect you from mill and can be involved in some combos (for example, Syr Konrad, the Grim+Basalt Monolith+Mesmeric Orb).