Soul of Mirrodin

The design bet here is redundancy: the same artifact tutor is stapled to the battlefield and to the graveyard, so removing the body only trades one activation for another. Kill it, and it fetches from the yard anyway; that repetition is what turns a slow six-drop into a reliable chain. Each activation is a five-mana tax that puts the target onto the battlefield tapped, so the card is built for the long game, not the turn it lands, and the tapped clause means whatever it finds can't attack or tap for value the turn it arrives. The 6/6 trample body is almost incidental to the engine, a clock stapled onto a toolbox so the card does something while you assemble the pieces. What it wants is a deck deep in artifacts costing five or less, where the tutor becomes a modal wish for whatever the board demands: a mana rock, a lock piece, a sacrifice payoff. The second ability is the honest one, because it costs the card itself, exiled from the graveyard, so the recursion is finite rather than a loop. This is a support engine wearing a beater's stats, and the friction that keeps it fair is the tapped condition on everything it drags out.