Spreading Algae

Color hosers usually point outward: a creature that hates on red, a spell that punishes blue's draw engines. This one points at land itself, and at one land type in particular. Attached to a land with the Swamp subtype, it makes that land a liability the moment its controller wants to use it: the trigger fires on tapping, so the only safe play is to leave the land untapped, which is to say not draw on that source at all. The recursion clause is the engine that turns a single one-mana enchantment into a recurring tax. Destroy the land, the Aura goes to the graveyard, and from there it returns to hand rather than staying dead, ready to lock down the next Swamp the opponent develops. The friction that keeps this honest is targeting: it reads the Swamp subtype, not the basic name, so it catches dual lands and shocklands carrying that type as well as basics, but a deck running black off lands with no Swamp subtype escapes it entirely. Against a heavy Swamp-based manabase, though, the loop is relentless, because the cost to redeploy is a single green mana each cycle while the opponent burns whole turns rebuilding. It is land destruction disguised as an Aura, recursion disguised as a downside clause, and a reminder that some of the meanest hosers of the period worked not by killing what an opponent had but by making the act of using it the trigger that destroyed it.