Rust Elemental

Four mana buys a 4/4 flier with no upfront restriction, but the ongoing tax is brutal: every upkeep the elemental devours another of your artifacts, and an empty larder taps it and drains four life. That clause turns a beater into a fuel gauge that demands fresh fodder each turn or starts billing you in life. It comes from a design language that treated artifacts as currency to be spent rather than permanents to protect, and the card wants a steady supply line of free or recursive chaff: tokens, cheap mana rocks, anything you would rather feed it than keep. The sacrifice is mandatory and untargeted, which makes it a sacrifice outlet you cannot switch off, the real wrinkle of the build: every death trigger and graveyard payoff it can power is gated only by how much fodder you manufacture before the life loss catches up. Run dry and it does not die; it simply taps and bleeds you, a slow clock ticking against its own controller. The whole thing is a wager that the conveyor belt stays stocked, and the moment the supply breaks, the elemental flips from threat to liability.