Before It's Turned Face Up

[OneAndOnly]

Disguise and cloak are cool mechanics, and make interesting successors to morph and manifest. I'm trying to generate a mechanic that takes their guessing games one step further:

Capricious Assassin -- 1BB
Creature - Spirit Assassin {U}
Deathtouch
Disguise 1B
As you turn Capricious Assassin face-up, before it's revealed, you may select an opponent. That player chooses even or odd.
When Capricious Assassin is turned face up, destroy target creature with an even mana value if "even" was chosen. Otherwise, destroy a creature with an odd mana value.
2/1


The theory would be that there would be a number of cards in the set, all which require a player to choose "even" or "odd" to determine an effect -- without necessarily knowing what that effect might be. It could be gaining life, drawing some number of cards, adding mana, putting counters on creatures -- or in this case, killing a creature that meets the criterion.

Whimsical Muse -- 1UU
Creature - Spirit Scholar {R}
Disguise 7U
As you turn Whimsical Muse face up, before it's revealed, you may select an opponent. That player chooses even or odd.
When Whimsical Muse is turned face up, if "even" was chosen, each player returns each permanent they control to its owner's hand. If "odd" was chosen, each player shuffles their hand and graveyard into their library, then draws seven cards.
2/2


Note that "even" and "odds" just represent a binary choice; I suppose more choices would be possible, but would start to cramp the text box. Whatever the words used, the choices have to be identical across the entire gamut of cards.


Impulsive Creation -- 1GG
Creature - Spirit Dryad {R}
Disguise G
As you turn Whimsical Muse face up, before it's revealed, you may select an opponent. That player chooses even or odd.
When Whimsical Muse is turned face up, if "even" was chosen, each player chooses a color, then adds an amount of that color equal to the number of cards in their hand. If "odds" was chosen, each player adds that much colorless mana instead. This mana doesn't empty as steps and phases end until end of turn.
1/4


Is it possible (or wise) to manipulate the morph/disguise ability this way? Would it have to be written into the rules for an as-yet-to-be-named future ability instead?

[WizardMN]

No, there isn't really a good way to handle this the way you want to. Asking players to take actions (even if not "game" actions) in the middle of you turning it face up is odd. It also introduces a lot of potential weirdness that if it is still face down, nothing is asking players to choose even or odd.

The rules don't really support hidden text having an effect on the game unless specifically called out (as Morph and its variants are). And current examples of "as this is turned face up" always assume it is face up when that effect happens so players know what is going on.

You could potentially do this via a new keyword and just bake the "choose even or odd" into the ability itself. "Pay the mana cost and then choose an opponent to choose even or odd. Once the choice is made, this turns face up". But then it limits design quite a bit and I am not sure how much it is worth it.

Since the opponent doesn't know what they are making a choice for, the choice itself is close enough to random. Obviously in constructed formats where only one of these cards is ever used, it is more telegraphed, but in a vacuum it can be equated to a random choice so you might as well just have a trigger to flip a coin with a reflexive trigger allowing for the targeting.

[OneAndOnly]

I suppose one way of looking at it is how granular the actual special action of turning a face-down card face up can be. "Casting a spell" goes through several steps, after all, and even playing a land as a special action (which can be done even in the middle of e.g. casting a spell) is an action that can be modified, as shock lands, tap lands, and so on have shown.

Sticking "If ~ would be turned face-up, ask an opponent to choose "even" or "odd," then turn this creature face-up instead" in the middle of the card's rules text would seem to work (and not have too much of a negative game effect if you tried to "trick" someone with a non-choice-involved morph/disguise card instead). It just seems odd to include it as a replacement effect for the card itself, rather than part of the rules for the mechanic.

Heard about the random-ness of it; I think part of the effort would be to make it just barely game-able; if a slight majority of effects in the set were preferable to be answered as "odd," for example, that might influence things, as well as abilities that allow you to peek at face-down creatures. As well as Break Open effects.