Waylay

Six power of flash blockers for three mana looks illegal until you read the exile clause, and the clause is the entire card. The Knights vanish at the next cleanup step, which means the only useful window is your opponent's combat: flash them in to ambush attackers, soak up a swing, trade three temporary 2/2s for whatever the other side committed. Cast it on your own turn and the bodies evaporate at cleanup before they ever attack; cast it during the opponent's end step and they are exiled that same turn, before you untap. So the design discipline isn't subtle, it's brutal: the rate is gaudy precisely because the creatures are defensive-only, alive just long enough to block once and disappear. That makes Waylay an early study in tokens with an expiration date, the template Wizards would later refine into bodies that gain haste and get sacrificed at end of turn rather than exiling at cleanup. The cleaner version lets the tokens attack; this one explicitly does not, which is why the seemingly enormous power output collapses into a single ambush. Read as a removal-adjacent combat trick rather than an aggressive play, it is honest about what it costs: you are buying one defensive turn at instant speed and paying for it by never getting an offensive one.