1. Bolt'ing a 2/3 Tarmogoyf with no Instants in the Graveyards
Tarmogoyf is one of the most expensive card in Modern, it needs to have some weird abilities to screw people up, right? So, when you cast a Lightning Bolt on a 2/3 Tarmogoyf with no Instants in the graveyards, what happens is: Bolt will resolve, putting 3 damage marks on the Goyf, and then when the spell resolves and someone gains priority, state-based actions will check that there are at least 3 card types in the yard, making Goyf a 3/4 with 3 damage marks on it. It's the same for any other cards that deals damage or -X/-X to a Goyf for example Anger of the Gods, Disfigure etc.
2. Fetching and Scrying
Serum Visions and fetchlands are commonly used in Modern. Have you ever cast a Serum Visions and forgot to crack your fetches? This is something that players might need to learn the hard way, as in, you need to make the mistake at least once before you can remember it. So, if you haven't make this mistake yet, do remember to crack your fetch prior to any scrying effects so that you won't waste the scry!
3. Valakut Triggers and Disrupting it
This card is usually played together with Primeval Titan and/or Scapeshift. Most of the time, when a player casts Scapeshift with 7 or more lands in play, people scoops up their cards and concedes. IMHO, this is not a good habit, you should always make sure they have enough mountains to deal lethal damage before you concede. Alright, how to disrupt Valakut triggers? Well, usually experienced Scapeshift players won't screw this up but I'll explain it for you if you haven't know about this. Let's say you are on 18 life and have a Tectonic Edge in play and the ability to activate it, while your opponent has 7 lands in play and he decides to cast Scapeshift, sacrificing 7 lands to fetch for a Valakut and 6 Mountains. Will you die? The answer is no. Why?
Let's read Valakut's triggered ability again: "Whenever a Mountain enters the battlefield under your control, if you control at least five other Mountains, you may have Valakut, the Molten Pinnacle deal 3 damage to target creature or player.". There's a so called "Intervening If" in the text (generally written in the form '[When/Whenever/At][Trigger Event], [if][Condition], [effect]'). This means that, Valakut will trigger when both the [Trigger Event] and the [Condition] are met, however, the [Condition] is checked again when the ability attempts to resolve. So, if your opponent has 6 Valakut triggers on the stack, you can Tect Edge one of his Mountain and 5 of the triggers no longer see the 6th Mountain in play when they are resolving.
4. Doing Stuffs in Response to Pithing Needle/Slaughter Games
Do you know, when does the player casting these spells name a card? Yes, they name it when the spell resolves. This means that, you cannot activate ability or play the named card anymore at the moment the card is named. This is pretty simple to understand I guess. So before these cards resolve, remember to stop your opponent and think abit on what you should do.
5. Destroying Blood Moon with no Basic Lands in Play
Blood Moon is usually used to screw up decks that play more than 2 colors. Sometimes, you suspect that your opponent sideboarded in Blood Moons but you can't fetch only Basic lands because you really need the dual lands to be able to cast all your spells. Assume you have something to destroy Blood Moon in hand (let's say Abrupt Decay), you can actually deal with Blood Moon without having any Basics in play. How does this work? We can't cast Abrupt Decay to destroy Blood Moon when Blood Moon is still on the stack right? Do you remember that we can float mana? So the trick is to float the required mana, let Blood Moon resolve, and then when opponent passes priority to enter the next phase, you cast the removal with the mana floated earlier to destroy Blood Moon. For this to work correctly, you need to communicate very clearly with your opponent or else you might screw up.
6. Arcbound Ravager/Cranial Plating Contradiction
When someone has Arcbound Ravager and Cranial Plating in play, sacrificing an artifact will grow Ravager but what if he/she forgot that it will shrink the Plating at the same time? It basically screws up the combat maths. If you are playing Affinity, I'm not sure whether you made this mistake before or not, but I've seen very experienced Affinity player making this mistake before. Here, I want to give a suggestion on how to prevent this. This method is actually inspired by my teammate Marcus Lee, whenever he puts a Cranial Plating into play, he puts a die on the Plating to represent the artifact count. I'm not sure whether or not Marcus uses this way to prevent the same mistake, but I think this is a good way to remind yourself about the artifact count when you want to sacrifice something to Arcbound Ravager.
7. Reveal your hand when Vendilion Clique resolves
Vendilion Clique entered the battlefield, your opponent pointed at the faerie, and then you revealed your hand......this is not how it's supposed to work, what if your opponent decides to target himself with the ETB trigger? So, make sure your opponent wants to target you with the trigger before you reveal your hand. Do take note that your opponent is not wrong to receive any information you chose to reveal to him. This works the same with discard spells like Inquisition of Kozilek and Thoughtseize, the controller can target himself to discard a card.
Now I have a bad feeling after saying these, I can foresee my opponents who read this article asking me who to target when I cast Thoughtseize......
8. Spellskite Shenanigans
In my opinion, this is one of the most complicated card in Modern. There are many things that you need to know regarding this artifact creature. For example, if your opponent casts Electrolyze, dealing 1 damage to you and 1 damage to Spellskite, you cannot redirect the 1 damage pointed at you to Spellskite. And as long as there's something on the stack, doesn't matter Spellskite is a legal target or not, you can pay 2 life to activate Spellskite's ability.
If I were to write full details on this card, I probably need another 3 hours. So, for more rulings about the card, you can read from here.
9. Siding in Grafdigger's Cage against Living End
If you didn't play against Living End much, you probably don't know about this. Grafdigger's Cage is not going to stop Living End from bringing back creatures from the graveyard. This is because Cage says "Creature cards can't enter the battlefield from graveyards or libraries.", but Living End exiles the creatures from graveyards first, and then bring them back from the exile.
10. Fizzling the Commands
Its pretty simple to fizzle spells that has only 1 mode. Like for example, if you somehow made Remand's target illegal, Remand won't give its controller a card. Now, how about spells with multiple modes? Very common examples are the Command Cycles from Lorwyn and Dragons of Tarkir, how do we fizzle these spells?
Let's take Cryptic Command as example, if your opponent casts the Command choosing modes 2 and 3. Responding to opposing Cryptic Command, you make the targetted creature Hexproof. Note that if modes 2 and 3 are chosen, there's only 1 target altogether, so Magic's ruling says whenever all targets of a spell are illegal, the spell fizzles and therefore Cryptic Command fizzles, your creatures are not tapped.
Another example, this time we pick Dromoka's Command. You cast Dromoka's Command, choosing modes 3 and 4 (assume both modes target 3 different creatures to fight and put counter). If your opponent kills one of the creatures you chose to fight, Dromoka's Command will still resolve by putting a +1/+1 counter on target creature. Fizzling 1 mode does not always fizzle the whole spell.
That's all for the 10 things I wanted to write. If you already know these before you read my article, congrats; if you learned something from my article, that's great. Either way, thanks for reading and all the best for the last WMCQ of 2016. Oh ya, if you are unsure about the rulings during tournaments, don't forget you can always call a Judge to clarify ya! See you all again next time.