Alrund's Epiphany

The extra-turn spell has always carried a design tax: raw Time Walk effects rarely close a game by themselves, so most of them either warp the mana curve to buy time or attach a payload that turns the free turn into damage. This one solves both problems at once. Two flying bodies mean the extra turn isn't empty; it's an evasive clock plus a full untap and draw, exactly enough to lock a game once you're chaining copies. The foretell mode is what makes the loop bearable: splitting the total cost across two turns (pay two now to exile it, cast it for later) lets you foretell early and hold up interaction, then cash in when the coast is clear, softening the tempo hit that usually keeps big extra-turn spells honest. The pattern it enables is the one every extra-turn deck eventually finds: cast one, untap, draw and refill, cast another, and let a growing squadron of Birds do the killing while you never actually pass to your opponent. That combination of a self-sufficient board and a discounted, telegraph-then-strike casting mode is why the card ended up on the wrong side of a Standard ban, cited for exactly the turn-chaining lock its Bird payload made too easy to assemble.