Mystic Remora

The most honest tax in the game, because it taxes you too. Cumulative upkeep is the mechanic that turned a self-destructing curiosity into one of the most elegant draw engines ever printed: the card asks your opponents to pay per noncreature spell or feed you cards, and it asks you to pay an escalating tax every turn or let it go. That symmetry is the whole design. The Remora draws hardest in the first few turns of a game (or the turns immediately after it lands), when nobody has a spare and the upkeep is still or , then quietly retires itself before the tax becomes ruinous. It is built to be a burst, not a permanent fixture, and reading the moment to sacrifice it is the entire skill the card demands. The genius is that both clauses point the same direction: the better it is doing, the more your opponents are paying to keep casting spells, which is also the window where you most want it alive. Cumulative upkeep has a reputation as a downside mechanic, the thing that killed Glacial Chasm and the various Ice Age survival enchantments by attrition. Here it is the load-bearing restriction that makes a one-mana repeatable Rhystic Study legal to print at all. Take that ramp away and the card is simply too good; the slow strangle is the price of admission.