House Guildmage

Both activated abilities want the same tap, and that single point of contention is the whole design. The body untaps once per turn, so it either holds a creature down or feeds the graveyard on any given rotation, never both. The blue mode keeps a target creature from untapping during its controller's next untap step: a soft lock that resolves combat math in your favor without touching the creature's current state, so it only bites when the target is already tapped or about to be. The black mode is repeatable Surveil 2, an engine that smooths draws and stocks the yard for whatever downstream payoff wants it. The Dimir split is what distinguishes this from most two-mode guildmages, which tend to run both halves off the same activation cost or the same color; here the disruption is priced in blue and the selection in black, so the mana you leave open telegraphs which job you mean to do this turn. The steep activation costs relative to a 2/2 are the friction: a fragile two-drop with two engines stapled to it would snowball fast if either mode came cheap, and neither does. This is a role-player for a grinding, incremental deck rather than one hunting a single payoff, doing slow, one-creature disruption on one axis and library maintenance on the other, but only ever one of them per turn.