Venerated Loxodon

Convoke's reward had always been the discount: every creature you tap shaves a mana off the cost, so the keyword traditionally paid you in tempo and nothing more. This rewrites the deal. Tap a board of small creatures to bring the price down, and the enters trigger pays you back a second time, permanently growing every creature that helped cast it. The convoke crew you spent isn't spent at all; it comes back bigger, and you've added a 4/4 on top. That double-counting is the design tension here. A wide go-tall payoff usually costs real mana or a real card; this one launders the same tapped creatures into both the cost reduction and the buff, which is why it punishes any board a sweeper hasn't already cleared. The buff being a durable counter rather than a temporary pump matters too: it survives the turn, so casting the Loxodon for next to nothing converts cleanly into a lasting threat. The honest restriction is that the payoff scales entirely with what you've already committed to the table. Cast it off no creatures and you've paid full price for a 4/4 whose trigger resolves against nothing; the card assumes a wide board and then overcommits to it. That's the whole bargain, and it's the cleanest statement of go-wide-into-go-tall the keyword has produced.