Undergrowth Recon

Every-upkeep recursion has a long green history, but most of it recurred creatures or artifacts; this narrows the target to the least-glamorous card in the deck and, in doing so, opens a loop that the more generous versions never could. A land goes to the graveyard, comes back tapped on your upkeep, and if you have an outlet that trades a land for value (a fetchland, a landfall payoff, a sacrifice-for-ramp effect), the same permanent can leave and return every turn indefinitely. The tapped clause is the timing tax that stops the loop from generating free mana the turn a land returns: you get the enters-the-battlefield triggers and the landfall, but not an untapped mana source on demand. Take that away and the engine collapses into infinite ramp; leave it in and the card stays honest. Against a lone fetchland it is a modest hedge that turns dead mana in the yard into slow, incremental board presence; against a graveyard full of utility lands with sacrifice payoffs it becomes a recurring value machine that resets each upkeep. What makes lands the right recursion target is that they are the resource players are most willing to feed to a sacrifice outlet, since a deck rarely needs every land it draws. The card asks for a graveyard worth mining and an outlet worth mining it with, and rewards a build oriented around the return trip rather than the land itself.