Zaxara, the Exemplary

X spells had always paid you exactly what you paid for: bigger Fireball, bigger Hydra, bigger draw off Blue Sun's Zenith, but the X was the effect and nothing more. This design turns the variable into a second payoff. The cast trigger reads the X in a spell's mana cost and builds a green Hydra token sized to it, so a Fireball cast for four leaves a 4/4 behind after the burn resolves. That reframes every X spell as a two-for-one, where the scaling half you already committed to now comes with a permanent that survives the spell. The mana ability does the enabling work, tapping for two of a single color to help float the piles those X costs demand, and it feeds the counterspell-and-draw variety of X spell as readily as the burn kind. Deathtouch on a 2/3 is almost incidental, a modest tax on attackers that keeps the body relevant in combat while the real engine sits on the stack trigger. The design coheres because the Hydra has no built-in value past its stats: it is not a Treasure maker or a card-draw outlet, just X worth of green power and toughness. That keeps the reward pointed at committing mana to the stack rather than dodging the payment. Both halves, the mana ability and the token trigger, aim at the same plan from opposite directions, making this the rare card built to reward paying X for its own sake.