The introduction of any new mechanic invariably means one thing: more rules to learn! If you are a student of the rules of Magic, the new "morph trigger" abilities in Legions should be easy enough to work through. But for the rest of us, here's a primer on how this new twist on an old ability will play out.

THE BASICS

Morph does not use the stack, but triggered abilities do. You cannot respond to morph, but you can respond to abilities that trigger whenever a creature is turned face-up. They are two separate events.

Using real cards as examples… You cannot respond to the act of turning a Shaleskin Plower face-up, but you can respond to the triggered ability of the Plower when it targets one of your lands.

Other things to remember:

Whenever a face-down creature leaves the in-play zone (it is destroyed, it is returned to your hand, it is removed from game), the face-down card must be revealed to all players. This is not considered turning the card face up for purposes of triggered abilities. Turning a card face up is specifically defined as going from face down to face up while in play.

considered turning the card face up for purposes of triggered abilities. Turning a card face up is specifically defined as going from face down to face up while in play. Abilities that trigger when a creature turns face up are not considered "comes-into-play" abilities, and will not trigger if the card comes into play face up from any zone, including your hand or the stack. Creatures with morph triggered abilities do not combo with Astral Slide or cards like Zombify.

A creature turned face up is not considered coming into play. Morphing Shaleskin Plower will let you destroy a land, but it will not let you draw a card from Wirewood Savage.

The abilities of creatures like Shaleskin Plower trigger even when they are turned face up via means other than morph. Ixidor, Reality Sculptor and Break Open are examples of cards that can turn face-down creatures face up without using the creatures' morph costs.

That should be enough information to let you play with the cards right out of the packs, but for those of you that need work on your rules knowledge—or just enjoy the intricacies of Magic's rules—try answering the questions below.

RULES QUESTIONS

1) You have a Serra Angel in play. Your opponent morphs his Skinthinner. Can you play Dark Banishing on the Skinthinner in response to prevent it from killing the Angel?

A) No. You cannot respond to morph as morph does not use the stack (Rule 502.26a). Morph is announced, the cost is paid, and the Skinthinner is turned face up. Once it is face up, its triggered ability goes on the stack and you will eventually get priority, but by then it is not a legal target for Dark Banishing, as it is a black creature. The Angel will die from the Skinthinner's ability.

2) You have a Serra Angel in play. Your opponent morphs his Skinthinner. Can you play Shock on the Skinthinner in response to prevent it from killing the Angel?

A) No. You cannot respond to morph as morph does not use the stack. Morph is announced, the cost is paid, and the Skinthinner is turned face up. Once it is face up, its triggered ability goes on the stack and you will eventually get priority, at which point you can respond with Shock. Shock will kill the Skinthinner, but because its triggered ability is already on the stack, your Angel will die when the ability resolves. Rule 402.6 states: "Once activated or triggered, an ability exists independently of its source (the card on which it's printed) as a pseudospell on the stack. Destruction or removal of the source after that time won't affect the ability."

3) You have a Ravenous Baloth in play. Your opponent morphs his Skinthinner and targets your Baloth with its triggered ability. Can you sacrifice the Baloth in response?

A) Yes. You cannot respond to morph as morph does not use the stack. Morph is announced, the cost is paid, and the Skinthinner is turned face up. But once it is face up, its triggered ability goes on the stack and you will eventually get priority, at which point you can respond by sacrificing the Baloth to itself to gain 4 life. The ability of the Skinthinner will then be countered because it no longer has a legal target.

4) You have a Ravenous Baloth in play, and your opponent has a Serra Angel. Your opponent morphs his Skinthinner. Can you sacrifice the Baloth in response, forcing him to target the Angel with the Skinthinner's ability?

A) No. You cannot respond to morph as morph does not use the stack. Morph is announced, the cost is paid, and the Skinthinner is turned face up. Once it is face up, its triggered ability goes on the stack and you will eventually get priority, but only after the target for the ability has been chosen, which will most likely be your Baloth. When you get priority, you can respond by sacrificing the Baloth to itself to gain 4 life. The ability of the Skinthinner will then be countered because it no longer has a legal target, but it will not be forced to target the Angel instead.

5) Your opponent has a Shifting Sky set to blue, a Serra Angel, and a face-down Skinthinner. You have an Engineered Plague set to Zombie. You play Break Open on the Skinthinner, turning it face up and causing its ability to trigger. Can he target the Skinthinner with its own ability before the Plague kills it, or is he forced to target his Angel?

A) No — he must target the Angel. When Break Open resolves, the Skinthinner is turned face up, but its triggered ability does not go on the stack until all necessary state-based effects resolve. Rule 420.3 states: "All applicable [state-based] effects resolve as a single event, then the check is repeated. Once no more state-based effects have been generated, triggered abilities go on the stack, then the appropriate player gets priority." So the blue Skinthinner dies due to the state-based effect of having zero toughness thanks to Engineered Plague, and then its morph trigger goes on the stack. At this point the only legal target is the Angel, which must be targeted.

CONCLUSION

Using some extrapolation and common sense, you can apply the above scenarios to most cards with morph triggers. If you still have trouble with some of the cards or the rules when the prerelease rolls around, talk to some of your local judges. They're there to help.