I think Mikaeus and Turn apply in timestamp order, so it winds up without Undying. that means Slaver is the only effect trying to return it, and will return it without a counter under your opponent's control.

that said, how Mikaeus and Turn apply doesn't really matter, because triggers are stacked active player first, and they resolve last-in-first-out, so as the non-active player, your opponent will resolve their Slaver trigger before your Undying trigger would resolve anyway.

as for what happens in combat, nothing exciting. your Slaver takes 2 damage.

Thanks for the quick reply, I was sure that it would of endedup being a 2/2 frog with undying...

I have a followup question: How come the +1/+1 from Mikaeus applies yet the undying does not?


V.

because layer 7 is a mess. ability-changing is layer 6 and, barring some exceptions that aren't relevant here, is all done in timestamp order. but P/T is layer 7 and has a bunch of sublayers. P/T-setting is done in 7b, so turn to frog makes it a 1/1 there. P/T-modifying is done in 7c, so Mikaeus's +1/+1 is applied there, after it becomes a 1/1.

Because by the time undying resolves its already been revived by dread slaver, so it doesn't do anything. That was my understanding anyway.

The Frog doesn't get the Undying because when it was a Zombie it had two instances of Undying. Turn to Frog removes both of those instances, and it continues to get the +1/+1 because it's still non-Human.

But as someone else already said, in the situation you described it wouldn't matter if the creature still had Undying. When multiple triggers happen due to a single event (in this case, Messenger dies to Dread Slaver creating an Undying trigger and Dread Slaver's trigger), players put their triggered abilities on the stack in APNAP order (Active Player, Non-Active Player). The Active Player is the player whose turn it is, and in the case of a multiplayer game players in turn order then put their triggers on the stack (so the player immediately to the left of the Active player, then the player to their left, so forth and so on until everybody has put their triggers on the stack). So in the case of a Messenger dying during your opponent's turn, they put their Undying trigger on the stack, then you put your Dread Slaver trigger on the stack, and abilities resolve from top to bottom, one at a time. Dread Slaver's ability would resolve first, giving you the Messenger. The ruling is simply saying that if the creature it's trying to return to the battlefield under your control is no longer in the graveyard when the ability resolves, nothing happens. And Undying is a convenient example to use because it's in the same block and can remove a creature card from a graveyard. But it's not saying that Undying always trumps the ability. That's not how Magic works. Only static abilities that use the word "can't" have anything akin to "trump" powers.

yeah, it's best to stay away from layers unless it's absolutely necessary.

613. Interaction of Continuous Effects

613.1. The values of an object’s characteristics are determined by starting with the actual object. For a card, that means the values of the characteristics printed on that card. For a token or a copy of a spell or card, that means the values of the characteristics defined by the effect that created it. Then all applicable continuous effects are applied in a series of layers in the following order:

613.1a Layer 1: Copy effects are applied.
613.1b Layer 2: Control-changing effects are applied.
613.1c Layer 3: Text-changing effects are applied.
613.1d Layer 4: Type-changing effects are applied.
613.1e Layer 5: Color-changing effects are applied.
613.1f Layer 6: Ability-adding effects, ability-removing effects, and effects that say an object can’t have an ability are applied.
613.1g Layer 7: Power- and/or toughness-changing effects are applied.
613.3. Within layer 7, apply effects in a series of sublayers in the order described below. Within each sublayer, apply effects in timestamp order.
613.3a Layer 7a: Effects from characteristic-defining abilities that define power and/or toughness are applied.
613.3b Layer 7b: Effects that set power and/or toughness to a specific number or value are applied.
613.3c Layer 7c: Effects that modify power and/or toughness
613.3d Layer 7d: Power and/or toughness changes from counters are applied.
613.3e Layer 7e: Effects that switch a creature’s power and toughness are applied.
613.4. The application of continuous effects as described by the layer system is continually and automatically performed by the game. All resulting changes to an object’s characteristics are instantaneous.

Here's the step-by-step in case it helps the OP or any lurking players just reading the thread.




So when Turn to Frog resolves on Geralf's Messenger, here is the change layer-by-layer (note 613.4, this is all continuous and automatic).

Start: Geralf's Messenger is a 3/2 Black Zombie with Undying

613.1a Layer 1: Not Applicable (N/A)
613.1b Layer 2: N/A
613.1c Layer 3: N/A
613.1d Layer 4: Add Frog (lose Zombie): Geralf's Messenger is a 3/2 Black Frog with Undying
613.1e Layer 5: Add Blue (lose Black): Geralf's Messenger is a 3/2 Blue Frog with Undying
613.1f Layer 6: No longer a zombie, so no Death Baron bonus. Then, in timestamp order, add Undying from Mikaeus, the Unhallowed, then lose both instances of Undying from Turn to Frog: Geralf's Messenger is a 3/2 Blue Frog
613.3a Layer 7a: N/A
613.3b Layer 7b: Becomes 1/1: Geralf's Messenger is a 1/1 Blue Frog
613.3c Layer 7c: Gets +1/+1 from Mikaeus, the Unhallowed (Non-human): Geralf's Messenger is a 2/2 Blue Frog
613.3d Layer 7d: N/A
613.3e Layer 7e: N/A

Final: Geralf's Messenger is a 2/2 Blue Frog with no abilities.