Mono-Red Aggro pressures fast with cheap creatures and burn like Burst Lightning, Lightning Strike, and Shock, so Split Up is a strong sweeper against their tapped attackers or untapped board depending on the situation. Avatar's Wrath airbends their entire board while preventing them from recasting those creatures until your next turn, buying crucial time against their aggression. Erode's free land is a real downside against an aggressive deck that benefits from extra mana for burn, and Nurturing Pixie's fragile 1/1 body dies to nearly everything they play. Keep our lifelink creatures like Sage of the Skies and cheap fliers like Momo, Friendly Flier to race their burn plan and stabilize the board.