Traveling Plague

An Aura that kills on a clock and then refuses to stay dead. The execution is inevitable rather than immediate: a plague counter lands at the beginning of every upkeep, including the opponent's, so in a two-player game the host sheds two points of toughness per full turn cycle. A larger body simply buys more upkeeps before it falls over. The memorable wrinkle is the recursion clause, which inverts the usual rules for creature-enchantments. Most Auras of this stripe are spent value: kill the host, the Aura hits the graveyard, the story ends. This one returns to the battlefield when its enchanted creature leaves, and the trigger hands the recursion to the controller of that creature, not to whoever did the killing. That detail is the whole tension. Hang it on your own creature, let the creature die, and you get to return the Aura and choose its next host. Aim it at an opponent and they inherit that same option in reverse the moment their creature falls: their controller returns it, their controller picks where it goes next. The counters reset on each new host, so the engine never stops, but it never reliably points one direction either. It is a poor answer to anything you need gone this turn and a slow, recursive grind against a board you expect to outlast: a removal spell that trades patience for permanence, with the catch that the player burying the host is the one who decides who suffers next.