This elegant engine turns simple creature-taps into an unstoppable loop of value, fueled by Glare of Subdual letting you target your opponents' creatures to lock down their boards. Whenever you tap one of those enemy creatures, Hylda of the Icy Crown triggers, giving you a powerful reward if you can pay the associated {1} mana. That's where Phyrexian Altar comes in, letting you immediately sacrifice the creature you used to activate the Glare to generate the exact mana needed to fund Hylda's triggered ability. By trading your creature for a fresh 4/4 Elemental token (or pumping your team and digging deeper), you leave behind a permanent presence while completely neutralizing your opponents' forces.