Akroan Mastiff

The whole game here is the recurring tap effect: a creature that, every turn, can lock down an attacker before it swings or freeze a blocker out of the way. That puts it squarely in white's tapper lineage, alongside Master Decoy and the various pacifism-on-a-stick designs, all of which share the same one-white-mana activation and the same tap-to-fire clause. What sets the Mastiff apart is mostly the chassis: a 2/2 body and a four-mana entry price for an effect that older versions delivered on a one-drop. Nobody is racing with this Dog. What it does is convert a board stall into a slow vise, repeatedly removing the biggest threat from combat without ever killing it. The cost of that repeatability is the tap-to-activate clause, which means the Mastiff has to survive a turn cycle and stay untapped to do its job, and it can only neutralize one creature at a time. Against a wide board it is a single thumb on the scale; against a deck leaning on one large finisher it is a genuine soft answer that costs no cards. That asymmetry, cheap and renewable against singletons, anemic against breadth, is exactly the balancing logic that has always governed white's tapper class: the activation stays trivially cheap precisely because each activation only ever buys you one creature's worth of tempo.