Tenacity

The untap clause is the line that turns a team pump into a tempo blowout. Read the rest of the spell and it looks defensive: a board-wide +1/+1 with lifelink is the kind of patch that absorbs an alpha strike and refills the total you were defending. But untapping every creature it touches rewires when those creatures can act. The play is to attack on your turn, empty your board into the red zone, and then flash this in during your opponent's combat to stand your now-untapped attackers back up as blockers, bigger and gaining you life for every point they deal. Most fight-or-fog instants resolve a single combat question. This one lets the same creatures be on offense and defense across two turns, which is a structural change to the math rather than a one-time swing. The four-mana cost is the tell: this is not a cheap reactive trick but a swing-the-game investment, priced as a full play rather than a reflexive cantrip. And it scales with width. A single extra untapped body is marginal; a board of them turns the +1/+1 and the lifelink into a decisive turn, which is the reason it belongs to go-wide white rather than any deck leaning on one or two large threats.