Fireborn Knight

The whole point here is that every mana symbol is hybrid, all four of them: this is a creature that mono-red can cast, that mono-white can cast, and that either color can pump without ever needing to splash the other. That is the trick that makes a double-strike body land where it otherwise could not. Double strike on a 2/3 already means it hits for four while surviving most cheap removal, and the pump ability is deliberately open-ended: each activation buys +1/+1 to both halves, so late in the game a flooded hand of lands turns into a creature that swings for six, eight, ten. The design lives entirely in that hybrid manabase. A card like this in strict Boros costs would ask for two colors of untapped mana on curve and then again to activate; writing every pip as collapses that requirement to "any four sources of either color," which is why the pump can realistically fire more than once. The body is the constraint that pays for the reach: 2/3 with double strike is a real clock but not an unanswerable one, so the mana sink is what elevates it rather than the stat line. It is a mana sink built for a deck that wants to spend its whole board on one attacker and dares the opponent to have the removal ready.