Mana Sink

Outlets that convert surplus mana into a meaningful effect, scaling with how much you can pour in. Covers {X} spells like Fireball, Exsanguinate, and Blue Sun's Zenith, repeatable activated abilities like Walking Ballista's damage and Staff of Domination's untap and draw modes, and storage payoffs like Helix Pinnacle that bank counters. The point is giving extra mana somewhere useful to go in long games. Broader than X Spell, which covers only spells with {X} in their mana cost; this also includes repeatable activated abilities and counter-storage outlets that have no {X} on the card at all.