Long-Finned Skywhale

The blocking restriction is the whole bargain here: a 4/3 flyer for four mana is an aggressive rate, well ahead of what a vanilla body would earn, and the price is that this creature cannot stand in front of anything on the ground. It is built to attack, never to anchor a defense. That clause is an old design lever for pricing evasive bodies cheaply: forfeit defensive flexibility, and the format tolerates an extra point of power. The trade-off is sharper than it first reads. A standard flyer can drop back to block a ground creature in a pinch; this one watches it walk past. Note that the restriction runs one direction only. On defense it can catch nothing but flyers, but on the attack it is still an ordinary creature with flying, so anything with reach can block it and trade. The evasion buys entry into the red zone, not immunity once it is there. The result commits its controller to the beatdown it was drawn into: a body that wins races and pressures life totals but offers no insurance when the race turns. It is honest aggression with the brakes removed, the kind of cheap, top-end evasion a tempo deck wants and a control deck has no use for.