114.1. Some spells and abilities require their controller to choose one or more targets for them. The targets are object(s), player(s), and/or zone(s) the spell or ability will affect. These targets are declared as part of the process of putting the spell or ability on the stack. The targets can't be changed except by another spell or ability that explicitly says it can do so.
So, an object, player or zone can become a target. Spells and abilities can be targeted. An instant or sorcery spell, an activated or triggered ability is targeted if and only if the word “target” is used in their text. Currently, exceptions to this are Aura spells and some abilities with certain keywords:
114.1a. An instant or sorcery spell is targeted if its spell ability identifies something it will affect by using the phrase “target [something],” where the “something” is a phrase that describes an object, player, or zone. The target(s) are chosen as the spell is cast; see rule 601.2c. (If an activated or triggered ability of an instant or sorcery uses the word target, that ability is targeted, but the spell is not.)
Example: A sorcery card has the ability “When you cycle this card, target creature gets -1/-1 until end of turn.” This triggered ability is targeted, but that doesn't make the card it's on targeted.
114.1b. Aura spells are always targeted. These are the only permanent spells with targets. An Aura's target is specified by its enchant keyword ability (see rule 702.5, “Enchant”). The target(s) are chosen as the spell is cast; see rule 601.2c. An Aura permanent doesn't target anything; only the spell is targeted. (An activated or triggered ability of an Aura permanent can also be targeted.)
114.1c. An activated ability is targeted if it identifies something it will affect by using the phrase “target [something],” where the “something” is a phrase that describes an object, player, or zone. The target(s) are chosen as the ability is activated; see rule 602.2b.
114.1d. A triggered ability is targeted if it identifies something it will affect by using the phrase “target [something],” where the “something” is a phrase that describes an object, player, or zone. The target(s) are chosen as the ability is put on the stack; see rule 603.3d.
114.1e. Some keyword abilities, such as equip and provoke, represent targeted activated or triggered abilities. In those cases, the phrase “target [something]” appears in the rule for that keyword ability rather than in the ability itself. (The keyword's reminder text will often contain the word “target.”) See rule 702, “Keyword Abilities.”
114.5. Spells and abilities that can have zero or more targets are targeted only if one or more targets have been chosen for them.
Repel the Darkness may have zero, one or two targets. If no targets were chosen, it is not targeted.
Dirge of Dread itself doesn't target, unlike its triggered ability which is targeted.
Arcbound Ravager doesn't target, however one of the parts of the ability with key word Modular is a targeted triggered ability: "When this permanent is put into a graveyard from the battlefield, you may put a +1/+1 counter on target artifact creature for each +1/+1 counter on this permanent.".
Blazing Torch doesn't target, nor does the permanent attached to the creature. However, the ability Equip does! The rule for Equip [cost] is: “[Cost]: Attach this permanent to target creature you control. Activate this ability only any time you could cast a sorcery.”.
When casting Spirit Mantle you will need to target a creature. the ability Enchant requires that.
The Enchant ability limits what the aura spell may target, and what the aura may be enchanting.
An aura that's already attached to a creature doesn't target it any more. Thus, if you cast Vines of Vastwood on a creature enchanted with Spirit Mantle, the Mantle won't drop off.
114.9. Spells and abilities can affect objects and players they don't target. In general, those objects and players aren't chosen until the spell or ability resolves. See rule 608, “Resolving Spells and Abilities.”
114.9a. Just because an object or player is being affected by a spell or ability doesn't make that object or player a target of that spell or ability. Unless that object or player is identified by the word “target” in the text of that spell or ability, or the rule for that keyword ability, it's not a target.
114.9b. In particular, the word “you” in an object's text doesn't indicate a target.
The word “you” in Bitterblossom's text isn't targeting you.
None of the Doll's abilities is targeted.
Day of Judgment doesn't target.
The Lion's triggered ability doesn't target although it does influence a creature.
Ryusei's triggered ability doesn't target.
“To distribute is to choose any number of permanents and players...”.
The text of Phyrexian Metamorph says: “You may have ~this~ enter the battlefield as a copy of any artifact or creature on the battlefield”, there is no word “target” in it. Therefore, it may copy a creature with Protection from Blue, Shroud and/or Hexproof.
Forge-Tender's ability does not target, so you may activate it even if there are no red sources around.
The Searchlight ability doesn't target and adds mana to the chosen player's mana pool, so it's a mana ability, it doesn't use the stack.
114.8. Some objects check what another spell or ability is targeting. Depending on the wording, these may check the current state of the targets, the state of the targets at the time they were selected, or both.
114.8a. An object that looks for a “[spell or ability] with a single target” checks the number of times any objects, players, or zones became the target of that spell or ability when it was put on the stack, not the number of its targets that are currently legal. If the same object, player, or zone became a target more than once, each of those instances is counted separately.
114.8b. An object that looks for a “[spell or ability] that targets [something]” checks the current state of that spell or ability's targets. If an object it targets is still in the zone it's expected to be in or a player it targets is still in the game, that target's current information is used, even if it's not currently legal for that spell or ability. If an object it targets is no longer in the zone it's expected to be in or a player it targets is no longer in the game, that target is ignored; its last known information is not used.
114.8c. An object that looks for a “[spell or ability] that targets only [something]” checks the number of different objects or players that became the target of that spell or ability when it was put on the stack (as modified by effects that changed those targets), not the number of those objects or players that are currently legal targets. If that number is one (even if the spell or ability targets that object or player multiple times), the current state of that spell or ability's target is checked as described in rule 114.8b.
Swerve doesn't check whether the current target is legal or not, it only wonders whether it's the only target.
You cannot target a spell that has multiple targets even if all of its targets but one have become illegal.
You may also not target a spell that targets the same object or player multiple times (Agony Warp).
Confound may target a spell that has multiple different targets as long a at least one of them matches the conditions — targets a creature. For instance, Searing Blaze.
If the target spell no longer targets a creature, its target is no longer a creature, or is no longer on the battlefield, Confound will be countered.
The Golem's second ability triggers every time a player casts an instant or sorcery spell that targets just one Golem (a permanent with subtype Golem). If the spell has multiple targets, and for each of those the same Golem is chosen (e.g., Seeds of Strength), the ability will trigger.
114.2. Only permanents are legal targets for spells and abilities, unless a spell or ability
(a) specifies that it can target an object in another zone or a player,
(b) targets an object that can't exist on the battlefield, such as a spell or ability,
or (c) targets a zone.
The spell of this wonderful aura targets an instant spell card in a graveyard.
114.3. The same target can't be chosen multiple times for any one instance of the word “target” on a spell or ability. If the spell or ability uses the word “target” in multiple places, the same object, player, or zone can be chosen once for each instance of the word “target” (as long as it fits the targeting criteria). This rule applies both when choosing targets for a spell or ability and when changing targets or choosing new targets for a spell or ability (see rule 114.6).
You must target two different creatures for Fulgent Distraction.
The same creature may be legally targeted twice for Agony Warp.
114.6. Some effects allow a player to change the target(s) of a spell or ability, and other effects allow a player to choose new targets for a spell or ability.
114.6a. If an effect allows a player to “change the target(s)” of a spell or ability, each target can be changed only to another legal target. If a target can't be changed to another legal target, the original target is unchanged, even if the original target is itself illegal by then. If all the targets aren't changed to other legal targets, none of them are changed.
114.6b. If an effect allows a player to “change a target” of a spell or ability, the process described in rule 114.6a is followed, except that only one of those targets may be changed (rather than all of them or none of them).
114.6c. If an effect allows a player to “change any targets” of a spell or ability, the process described in rule 114.6a is followed, except that any number of those targets may be changed (rather than all of them or none of them).
114.6d. If an effect allows a player to “choose new targets” for a spell or ability, the player may leave any number of the targets unchanged, even if those targets would be illegal. If the player chooses to change some or all of the targets, the new targets must be legal and must not cause any unchanged targets to become illegal.
The ability of this goblin functions in “all or nothing” manner: you either change all targets or leave everything as is.
Sideswipe allows changing any number of targets of a target spell.
Storm allows choosing new targets for each copy. They do not have to be changed.
You may not change Cryoclasm's target from a Plains to a Forest.
When a modal spell's targets are changed, the modes aren't. If the Charm's mode was “Counter target instant spell”, the target may only change to another instant. You cannot destroy an artifact, for example.
Thrun spell on the stack may be chosen as a target for countering spells and abilities. But Thrun permanent on the battlefield may not be chosen as a target of a spell or ability controlled by an opponent.
Spells and abilities countered through the loss of legal targets (Fizzling)
608.2b. ...The spell or ability is countered if all its targets, for every instance of the word “target,” are [now] illegal...
In Magic slang they say in this case the spell “Fizzled”.
When casting Cryptic Command, you choose “return target permanent to its owner's hand” and “draw a card” as modes, and as the Command resolves the permanent is an illegal target. In this case, the Command is countered and you do not draw a card.
If however you choose “counter target spell” and “return target permanent to its owner's hand”, even if the permanent is an illegal target, the Command will resolve because it still has a legal target. The target spell will be countered as the Command resolves.
Multani's Presence illustrates the difference between “fizzled” and “resolved without any kind of effect”.
Emrakul cannot be countered, but it doesn't mean it can't be targeted with a countering spell. If you target the Emrakul spell with Cancel, Cancel will resolve safely, but produce no effect. In this case, Multani's Presence's trigger will not go off.
In case with a fizzling Cryptic Command, Multani's Presence's ability triggers and you draw a card as it resolves.
702.18a. Shroud is a static ability. “Shroud” means “This permanent or player can't be the target of spells or abilities.”
This ability has no other meaning, no hidden tricks or anything. It doesn't prevent damage to a creature with Shroud, nor makes it impossible to destroy the permanent with Shroud, nor counter a spell of a permanent with Shroud. All it does is prevent targeting.
Thundermaw Hellkite's ability doesn't target. An opponent's flying creature with Shroud that falls under its effect will take damage and become tapped.
Wrath of God deals with creatures with Shroud easily. It doesn't target.
Contagion Engine will put -1/-1 counters on a creature with Shroud as it targets a player, not a creature.
An Aura permanent doesn't target, so if there is a possibility to attach it to a creature with Shroud, it is legal. Only an Aura spell targets. Giving an enchanted permanent Shroud is pointless if you just want to make it drop the Aura.
An Equipment permanent doesn't target either. As Sai of the Shinobi's trigger resolves, you may attach it to a creature with Shroud, but you cannot attach it through the targeted ability “Equip”.
Shroud is a static ability that functions only from the battlefield. Countering a spell of a permanent with Shroud is feasible by any mage.
A creature with Shroud that has been dealt damage by a source with Deathtouch will be destroyed as any other (unless it has Indestructible).
Magic 2012 edition brought us a new keyword: Hexproof.
702.11b. “Hexproof” on a permanent means “This permanent can't be the target of spells or abilities your opponents control.”
702.11c. “Hexproof” on a player means “You can't be the target of spells or abilities your opponents control.”
A creature with Hexproof cannot become the target of spells or abilities your opponents control.
You may target it with your own spells and abilities as normal.
Just as Shroud, Hexproof by itself doesn't save the creature from taking damage or getting destroyed. It doesn't influence the spell on the stack: a spell of a permanent with Hexproof may be countered. All it does is prevent targeting the opponent's permanent.
A permanent with protection from [quality] may not become the target of spells with that quality, or of abilities from sources with that quality.
For instance, if you control Runed Halo for which Mistbind Clique was called as it entered the battlefield, your opponent will have to target himself with her triggered ability and tap his own lands.
Note that protection doesn't save from spells of mass removal that do not target and do not deal damage.
Your opponent casts Naturalize targeting an artifact. Can the target be changed to an enchantment through Imp's Mischief?
You cast a Very-Important-Spell, an opponent targets it with her Cancel. Nothing else is on the stack. Can you save your Very-Important-Spell using Shunt?
An opponent attacks with Boggart Ram-Gang, You block with Drove of Elves. Will the elves get a -1/-1 counter?
May your opponent choose Pincher Beetles under his control to "Fight in Arena" if you control Arena? How about if he does?
May any of Helix Pinnacle's abilities be countered with Trickbind?
Can your Stonecloaker return your Calciderm to your hand?