Gandalf the Grey

The design problem with a wizard whose whole character is measured discretion (the one who holds back, who does the small right thing rather than the large flashy one) is that Magic normally rewards the opposite. The modal spell-trigger solves it elegantly: every instant or sorcery you cast forces a choice among four options, but each mode can be chosen only once, so the engine spends itself down over a game. The tap-or-untap line is the humble opener, the copy line is the payoff that turns a good spell into two, the three-damage-to-each-opponent line closes a race, and putting Gandalf on top of his owner's library is the deliberate reset that lets you begin the ladder again after redrawing and recasting him. That last mode is the character beat rendered as rules text: Gandalf leaving, and returning when needed. Structurally it makes the trigger renewable at the cost of a card and five mana, which keeps the engine from becoming a permanent copy machine while still promising the full sequence later. The 3/4 body is almost beside the point; the reason to run this is the spellcasting subgame it builds on top of every cantrip, burn spell, and counter you were already casting, where each cast asks not "what does this do" but "which of my four remaining privileges do I want to spend it on."