Lashweed Lurker

The eight-mana sticker is a fiction the card almost never pays. Emerge is the whole hinge: sacrifice a creature, subtract its mana value from the cost, and the Lurker arrives priced like the body you fed it rather than its bloated printed total. The reward for that conversion is a cast trigger that puts any nonland permanent on top of its owner's library, a tempo swing meaner than a return-to-hand: the owner has to spend a draw step and a turn redrawing what they already paid for, and you get to choose the worst possible thing to strand up there. Because emerge keys off the sacrificed creature's mana value rather than its power, a fragile, expensive utility creature makes better fuel than a fat attacker, which inverts the usual instinct about what to throw away. And because that bounce resolves off the act of casting, it clears the target even if a counterspell answers the 5/4 first: the permanent is already packed away by the time the Lurker itself gets stopped. That turns the whole thing into a way to launder a value creature you no longer need into a hard tempo play, with a 5/4 beater attached if it sticks. Among the colorless Eldrazi that split their casting cost across two colors, this sits at the cleaner, more interactive end of the experiment: cost reduction tied to an act of sacrifice rather than to ramp.