%% For the sake of having some objective standards, "practical" and "impractical" should be evaluated with tournament performance in mind. If you're not sure about an example, bring it up on the discussion page.
''MagicTheGathering'' is ''the'' [[LongRunner oldest]] collectable card games on the market, with thousands of unique cards to choose and build a deck from. Naturally, many of them ''look'' more effective than they actually are.
* The entire purpose of the Commander/EDH format is to play a longer game in which a lot of these cards can be used more practically.
* A lot of combos are like this: they'll win spectacularly, but only if you can play four different cards on the same turn that require three different colors and no counterspells from your opponent. Guess the odds on that actually happening. This is the aim of [[PlayerArchetypes Timmy/Johnny players]], especially those who combine Timmy's love of big flashy effects and Johnny's love of convoluted combos. Even if their combo only works once, they're happy.
* [[http://magiccards.info/fut/en/8.html The]] [[http://magiccards.info/query?q=pact+of+negation&v=card&s=cname entire]] [[http://magiccards.info/fut/en/78.html cycle]] [[http://magiccards.info/fut/en/103.html of]] [[http://magiccards.info/fut/en/139.html Pacts]] from ''Future Sight'' also fall into this: They're very powerful spells for free, but you have to win the game that turn or be certain you'll have the mana available next turn to pay for it, otherwise it's an [[NonStandardGameOver instant loss]]. Pact of Negation sees tournament use to keep instant-win combos from being interrupted, while the rest are niche cards at best & unusable at worst.
* Any spell that requires more than two types of colored mana can become this. Three-color spells like Cruel Ultimatum (mentioned further down) can be worth the hassle, but four- and five-color spells are unlikely to make up the disadvantage of playing with a four- or five-colored deck and hoping that the opponent doesn't just steamroll you as you try to set up your field.
* [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=193535 Spawnsire of Ulamog's]] ability lets you play as many of the humongous Eldrazi cards as you want, right now, for no extra cost, and without even having to have them in your deck... if you can somehow get the whopping ''twenty'' mana it takes to activate it. It wouldn't be terrible, except that having all of your Eldrazi at once is almost always overkill--for just over half the mana cost as the Spawnsire of Ulamog, you could just cast [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=261321 Ulamog]] itself and skip the middleman.
* The Elder Dragons ([[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=201177 Arcades Sabboth]], [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=201184 Chromium]], [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=201213 Nicol Bolas]], [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=201215 Palladia-Mors]], and [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=201243 Vaevictis Asmadi]]), five cards with powerful stats and splashy effects but which were almost impossible to play thanks to their casting costs ''and'' which required a constant influx of mana every turn to keep them in play.
* Any of the legends from ''Legends'' could be considered when they first came out: Large creatures with splashy effects, but very expensive & frequently with upkeep costs.
** They're not even that practical anymore: Modern creatures may not have as many abilities as the ones from ''Legends'', but they can be larger & cheaper, without an upkeep cost or other drawback. Magic's early card designers didn't appreciate that giving a big creature a high mana cost was already a drawback, hence why cards like the elder dragons, [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=159241 Polar Kraken]], [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=108920 Leviathan]] and [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=184593 Marjhan]] have such hideous drawbacks in addition to their huge cost.
* Much like the Elder Dragons, [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=266154 Nicol Bolas, Planeswalker]]. His +3 ability is to utterly destroy any non-creature card in the game (in addition to providing an obscene boost to his Loyalty total), and his ultimate effectively left your opponent topdecking with very little resources. The catch? You need 8 mana, 4 of which were split into three different colors. That's never been an unattainable feat, but the same block had Nicol Bolas' signature spell [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=376288 Cruel Ultimatum]] in the same colors for one less mana that would almost always win the game when it was cast; Nicol Bolas, while still a kitchen table favorite to this day, was left on the sidelines as all the competitive decks opted for the seven-mana sorcery instead.
** On the note of planeswalkers, their final abilities are either impressive or game-ending, but needs multiple turns of constant defense such that you can accumulate enough loyalty counters to pay the cost. Keep in mind that most planeswalkers' loyalty-increasing abilities offer marginal defenses on their own. The few planeswalkers who can use their final ability much sooner typically have a more underwhelming effect. Thus, a planeswalker is often evaluated by their first few abilities which are often available as soon as they enter the battlefield.
* [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=43548 Darksteel Reactor]] and [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=150992 Helix Pinnacle]] are big, flashy, nigh-unkillable instant-win spells, but most of the time, the game is already over long before they finish charging, and if it goes that long, you could probably win just as easily with any generic flying creature.
** ''Oath of the Gatewatch'' introduced another one with [[http://www.magicspoiler.com/mtg-spoiler/hedron-alignment/ Hedron Alignment]]: It's very unusual to draw all 4 copies of a card in a normal match, getting cards ''into'' exile is tough, and even then one discard spell, or a spell removing cards from exile or graveyard, from your opponent can ruin the entire thing.
** Most InstantWinCondition cards end up being impractical. They range from [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=193467 suffering enough damage to reduce yourself to exactly 1 life]] to [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=29978 winning ten coin flips]]. While it's incredibly satisfying to use these spells and actually have them go off, and [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=83133 Battle of Wits]] has even seen some high-level tournament play, it's much more practical to use conventional means. In particular, most of these shenanigans requires you to do things that would have won you the game anyways, like [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=180620 pumping a creature to 20 power]] [[note]]Although that card has other effects that make it slightly more useful[[/note]]. Attacking the opponent directly with a creature with 20 power usually means victory.
** Also, most instant-win cards only activate if their condition is true at the start of your turn, which means your opponent usually has a full turn to either destroy the card, invalidate the condition or finish you off (unless you can somehow create the right condition at instant speed just before the end of their turn).
** Battle of Wits has the unique disadvantage of giving away your main strategy before the game even starts. For it to have any chance whatsoever, your deck needs to have at least 201 cards in it, and for a realistic chance it should be a bit more than that. Most players stick to the bare minimum of 60 cards in their deck, to maximize their chance of drawing the card(s) they really want. The difference is ''very'' visible, and an opponent with the right cards can start planning right away. If you're [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=394026 exceptionally]] [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=233041 unlucky]] you could be onto Plan B before your first turn.
*** One rather amusing way to play Battle of Wits would be to pair it with Spawnsire of Ulamog's 20-mana activated ability to bring out ''200 copies of [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=397905 Emrakul, the Aeons Torn]]''. Being a Legendary creature, all but 1 copy of Emrakul would immediately need to be sacrificed to the Graveyard... but due to her triggered ability, '''all copies would go to the library instead''', fulfilling Battle of Wits' condition and winning the game. This victory method is impractical not only due to the aforementioned drawbacks of using Spawnsire of Ulamog's ability, but also because copies of Emrakul, the Aeons Torn retail for roughly $25 each - and as such, would cost roughly $5,000 in cold, hard cash. Getting 200 copies in order to use the combo is something only for a bored billionaire to go for. It also wouldn't work in tournament settings, where, in addition to the impracticality of 20 mana, Spawnsire of Ulamog can only summon Eldrazi in your 15-card sideboard and you're limited to 4 copies of a card in your deck + sideboard. A casual setting with more relaxed rules might allow it, if you just wanted to entertain some of your friends by casting 200 Eldrazi. In any case, you wouldn't really need Battle of Wits to win anyway- Emrakul's extra turn effect triggers when you cast it, so even using Spawnsire of Ulamog to cast 200 Emrakuls gives you 200 extra turns.
*** Another issue unique to Battle of Wits that makes it almost unplayable in tournaments is ''shuffling'', of all things. Sufficiently randomizing a ~300 card deck is exceedingly difficult and time-consuming. Battle of Wits decks are often filled to the brim with tutoring cards and fetchlands to give something resembling consistency to such a huge deck, and the deck must be thoroughly shuffled after each time one is used, playing it in a timely fashion in paper is nearly impossible.
* Triggering the ability of [[http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Door%20to%20Nothingness Door to Nothingness]] can be especially difficult. You have to have two mana of each of the five colors to trigger its ability, which is far from trivial to achieve. You also have to leave it sitting on the table for at least one full turn and hope it doesn't get destroyed. However, if you do succeed in this, the target player loses the game on the spot.
* The Epic spells from Saviors of Kamigawa are five spells with awesome, flashy effects that repeat themselves every turn for the rest of the game after you cast them the first time. The drawback is that you can cast the Epic spell every turn, but ''nothing else''--you can't cast any new spells. [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=87598 Enduring Ideal]], the white one, did break out into the tournament scene for a short time, but the other four never caught on.
* The card [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=226721 Chalice of Life/Chalice of Death]] can kill an opponent in four turns--assuming you can keep your life from going to zero AND keep the card on the field long enough to transform it, AND keep the opponent from gaining life, not to mention the fact that you have to wait for your life to get to THIRTY just to use it...
** Thirty if you're playing using the default starting life total of twenty. The card itself states "ten more than your starting life total", so if you're playing a format where you start off with more that twenty life, i.e. Two-Headed Giant, Commander, Horde Magic, you're going to be at it for a while even if you've built a deck specifically around the Chalice.
* The [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=9844 B. F. M. (Big Furry Monster)]] from the joke set ''Unglued'': BBBBBBBBBBBBBBB [[labelnote:*]]that's 15 black mana![[/labelnote]] is a huge cost, even for a 99/99; most games would be wrapping up by the time you got that kind of mana. Since each half is useless on its own, most reanimation spells don't work & [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=10655 Victimize]] is the only way to get it into play via the graveyard. It's not even clear if alternate costs like [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=50117 Fist of Suns]] would work, since it's unclear if each card is a separate spell and the only source for Un-set "errata" is [[http://markrosewater.tumblr.com/post/128587977963/un-question-would-it-be-possible-to-use-fist-of Mark Rosewater speaking semi-officially on Tumblr]].
* [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=40545 Phage the Untouchable]] got a lot of attention when she first debuted due to her abilities; she instantly kills any creature she deals damage to, and any player that takes damage from her loses the game. To counterbalance this, Phage also has an ability where if she isn't played from her controller's hand, ''that player'' loses the game. She's such a hassle to use that she got the name [[FanNickname Phage the Unplayable]]. Opponents will probably have much larger creatures by the time you have 3BBBB handy to play her & she doesn't have indestructible, first strike, or trample, combos to get her into play from the graveyard or library are very complicated and easy to spot, and she's still vulnerable to counterspells, blocking, instant-kill spells, and so on. Abilities in later editions render her deathtouch ability almost moot, and there are so many ways to get rid of her that it's almost not worth the trouble of setting up a combo to summon her.
** She's not even usable in Commander, a format where unusual cards and interactions thrive, because casting her from your command zone does not count as casting from your hand... costing you the game on the spot [[note]]Any deck with Phage as its commander would be mono-black, leaving only [[http://magiccards.info/nph/en/162.html Torpor Orb]] to make her playable, and it's entirely possible to not draw it in a 100-card singleton deck.[[/note]].
** And just to twist the knife further, should you somehow manage to get her into play, your opponent can still "blink" Phage (that is, exile her and then return her to the battlefield, such as with [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=15127 Flicker]]). The result? Her first ability will trigger, see that you didn't cast her from your hand, and ''kill you''.
* The ''Invasion'' block's 5-color theme resulted in a ton of these:
** [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=25797 Draco]] was a 9/9 for 6 mana.....provided you were had all 5 basic land types in play. Since Domain checks for land types & not mana colors, the creature & artifact mana sources prevalent in the block couldn't help; you were also stuck with a nasty upkeep cost if you didn't have all 5 land types.
** In the same vein, Apocalypse had [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=27231 Last Stand]]: Each of its 5 effects would have been great on its own[[note]]Drawing 1 card for each Island you control would be devastating in the late game, for example[[/note]], but putting them all on 1 WUBRG card [[note]]a card that costs one of each color of mana[[/note]] results in a spell that really doesn't have a practical use: 5-color decks tend not to have too many of any 1 land type[[note]]Some 5-color decks run extra Forests because of green's access to mana acceleration & land tutoring, but that doesn't help when Green's ability is arguably the worst & there are easier ways to get many or infinite tokens[[/note]], so the spell's tough to cast & generally worse than low-cost cards in each color.
** Invasion's [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=23206 cycle]] [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=23207 of]] [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=23208 three-colored]] [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=23209 legendary]] [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=23210 dragons]]. 6/6 with flying and a triggered ability for 6 was a good deal at the time & still is in Block Constructed, but the mana cost was 3CDE-even the set's strong multicolor theme couldn't make these viable.
* [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=386731 Zurgo Helmsmasher]], the leader of the [[ProudWarriorRaceGuy Mardu]] from Khans of Tarkir, is a devastating hasty beatstick that is almost guaranteed to get at least one attack and gets bigger every time he kills something. Unfortunately for him, a) even in decks that can meet his tri-colour demand he's sharing space with [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=386501 Butcher of the Horde]], which is tougher, cheaper, and can be used in multiples, and b) he dies so easily to removal in the enemy turn, even if he kills a chump blocker, that his lack of trample makes him largely useless. (He even dies fairly easily in his own turn if he's coming up against another deck with black in it - black gets a lot of -X/-X instants that do an end-run around his indestructibility.) Ironically, his alternate-timeline self from Dragons of Tarkir, which includes flavor text that he's fallen so far his enemy thinks he's NotWorthKilling, is so BoringYetPractical (a 2/2 for 1 red, or dashed for a red and a colorless, with the only drawback being it can't chump block) that it became an instant mainstay in red decks.
* [[http://magiccards.info/query?q=Platinum+Angel&v=card&s=cname Platinum Angel]], a 4/4 flying creature with the effect "You can't lose the game and your opponent can't win the game". The catch? A mana cost of 7 and no protection against creature and/or artifact destruction/removal.
* [[http://magiccards.info/query?q=!Savor+the+Moment Savor the Moment]] from ''Shadowmoor'' lets you take an extra turn for only 1 more blue mana than Time Walk.... but at the cost of skipping your untap step. There might be a deck that could abuse this with upkeep or other automatic effects, but in most cases skipping the untap step reduces the extra turn to just drawing a card (or doing things postponed from the last turn).
* [[http://magiccards.info/in/en/135.html Yawgmoth's Agenda]] lets you cast cards from your graveyard, making it a recurring version of the game-breaking [[http://magiccards.info/us/en/171.html Yawgmoth's Will]]. The catch? You can only cast one card per turn. So few decks can work around this constraint that it's near-useless rather than overpowered.
* [[http://magiccards.info/cedi/en/22.html Lich]] effectively makes it impossible for you to lose the game while it's in play, provided you have enough permanents to feed to it (which is easily accomplished with a number of different deck types). The problem is that your opponent needs only a single disenchantment, or any other card that destroys enchantments, to instantly end the game.