Boldwyr Intimidator

Most evasion is static: flying, fear, the old intimidate keyword, a creature that either can or cannot be blocked from the moment it resolves. This Giant rewrites the rule into something you spend mana on, turn by turn. The static line, Cowards can't block Warriors, does real work the instant it hits the table: this Giant is itself a Warrior, so it already cannot be stopped by anything you have turned into a Coward. For a single red, you convert a would-be blocker into a Coward who legally cannot stop your Warriors; for two more, you can hand a creature the Warrior type to feed the same restriction or to enable Warrior-tribal payoffs elsewhere. The crucial detail is the clock: blocking restrictions have to be locked in before blockers are declared, so the Coward conversion is a declare-attackers-step play, not a response to how an opponent chooses to block. It is evasion negotiated on the stack rather than printed on a keyword line.

The flavor is the whole joke executed as a rules engine: Cowards can't block Warriors reads like a children's-book aphorism until you notice the card hands out both types on demand, to your creatures and theirs alike. That self-referential design, a creature whose abilities only matter because of its other abilities, belongs to an experimental, type-changing era where cards were built to show off templating tricks as much as to win games. The 5/5 body for seven is almost beside the point; the card is a costed instruction for turning combat math into a question of who counts as brave.