Grimclaw Bats

Pay-life pumps were a small fixture of black's evasive creatures long before this one, but the math here is plain: every black mana and one life buys a temporary point on each side of the stat line. The body asks you to keep feeding it, and the life cost means the clock runs against you as well as your opponent. What it does that a vanilla flier does not is convert a flooded hand into reach: late in a game where extra mana has nowhere to go, those leftover swamps become incremental damage, turning a token-sized threat into something that can punch through for lethal in a single attack step. The trap is committing the mana and life before the swing resolves: a 1/1 base means a single instant-speed removal spell during the declare-attackers step blows out the investment, costing you the creature, the mana, and the life all at once. The disciplined line is to pump only after blocks are declared and the path to damage is clear, then let the bonus reset. That same fragility makes it a poor blocker, since no defender wants to bleed life to trade, and a fine attacker, which is exactly the role a small flier wants. As a piece of black aggro design it is honest about its limits: cheap evasion that scales with mana you would otherwise waste, paid for in a resource the deck is usually happy to spend.