Staff of Domination

What makes the staff dangerous is the first ability, the one that costs no tap and no card: spend one to untap it, and every other line on the card stops being a once-per-turn effect. The other four abilities are deliberately mundane in isolation (gain a life, untap a creature, tap a creature, draw a card), priced so that none of them threatens anything on its own. The untap clause is the hinge that turns the whole thing into a combo engine. Feed it enough mana production (a creature that taps for more than the activation costs) and the staff becomes infinite: infinite untaps, infinite life, infinite card draw, and an infinite tap-down lock that can hold an entire board hostage. This is a recurring design problem with Tinker-style payoff artifacts: a card that does five reasonable things becomes one unreasonable thing the instant a single ability can refund its own activation. The staff is the textbook study in that trap, which is why it reads as a value rock and plays as a win condition. The discipline in the design is that the mana threshold is real; without an outsized mana source the staff is exactly the modest toolbox it appears to be, drawing one card for five and untapping one creature for three. The gap between those two states is the entire story of the card.