Kellan, Planar Trailblazer

Every version of Kellan that Wizards has printed leans on the same joke: this is the kid who cannot sit still, whose whole story is picking up a new job every act. This one hard-codes the arc into a pair of activated costs. The 2/1 body starts as a Scout, pays to become a Detective, then pays again to become a double-striking Rogue, each step written as a permanent type change on a single creature rather than a stack of separate bodies. The design tension is that none of it advances your board: you are sinking mana into one attacker instead of developing width, so the payoff has to justify the tunnel vision. It mostly does through the middle stage, where connecting in combat exiles the top card and lets you play it that turn, lands included, a red impulse-draw stapled to a body that already wants to be swinging. The final upgrade to double strike doubles down on that middle stage: an unblocked Rogue triggers the exile twice, turning one connection into two cards. But the creature never gains evasion, so a chump block shuts the whole engine off, and that is what keeps the design honest alongside the deeper problem: both activations funnel through the same one-drop that a single removal spell erases. Because neither ability carries a timing restriction, you can hold the mana and change forms after blockers are declared or in response to a trick; the sink is flexible, but it is still a sink asking for the rest of your game.