Moroii

A 4/4 flier for four mana was an aggressive body for an early-era multicolor uncommon, and the design knew it. The upkeep life loss is the tax that pays for the rate: every turn you keep Moroii on the battlefield, it bleeds you for one, so the clock you point at your opponent runs against you too. The strategic axis runs entirely on that conflict. A beater this size wants to be cast and forgotten, but the drain turns it into a card you race to make irrelevant, either by closing the game before the math catches up or by sacrificing, blinking, or bouncing it once it has done its work. The flavor reads cleanly: a vampire that costs its master a little blood to maintain. It belongs to a long line of undercosted creatures saddled with a recurring downside, the lineage that runs through Juzam Djinn and its imitators, where the body is priced as if the drawback did not exist and the player is left to manage the bleed. Moroii sits at the gentler end of that family (one life a turn rather than several), which makes the drawback less a liability than a soft deadline: a reminder that the best thing you can do with a creature this efficient is win quickly enough that the upkeep trigger never gets to matter.