Magic: The Gathering reveals must-have sideboard card in 'Karn's Sylex'

sportskeeda.com:

It can often be hard to determine what to put in a sideboard in Magic: The Gathering. Occasionally, though, a card comes along that simply must be used in nearly every sideboard, no matter what. These are known as staples, and MTG’s Dominaria United just released a must-have Mythic Rare.

Karn’s Sylex is a Legendary Artifact that can put a halt to several strategies involving paying life for spells, and also puts a number of other strategies to rest. It is an incredibly powerful card, and all players should try to own it.

This colorless artifact answers a variety of needs in Magic: The Gathering, making it important in the upcoming meta shift. With Dominaria United continuing the slow trickle of Phyrexian-themed cards, cards that can pay for abilities with life are going to be more common.

What can this card do, though?

Phyrexian cards often feature Phyrexian Mana, which can be paid with life instead of tapping for mana. Karn’s Sylex completely negates that feature, slowing those decks down considerably.

It is also not uncommon to see Commander decks and other Standard decks offer abilities that are paid with life. One card that is often looked back on is Gristlebrand, which can pay seven life to draw seven cards.

This is not the only great feature of the card, however. The final ability allows the player to tap this card, tap X mana, and destroy all nonland permanents with a certain cost or lower. This might sound expensive until players realize that they can tap 0 and use it to destroy all token creatures in play.

With this revelation, the Magic: The Gathering card has even more power. That is why it comes into play tapped. It would perhaps be far too powerful to allow it in play untapped, as an immediate response to token