Adrenaline Jockey

A Minotaur that punishes people for casting on the wrong turn. The first ability is a tax on interaction, but a precise one: it fires only when a player casts a spell during a turn that isn't theirs, and it deals 4 damage to them for every such spell. That narrows the crime to instants, flash creatures, and anything else jammed on your turn or in your end step, which is enough to make a control player think twice about holding up a counterspell they were planning to cast reactively. Because it is damage rather than life loss, the clock can be blunted: prevention effects, fogs, and damage-modifying enchantments soften the tax in a way they never could against a straight payment, so the punisher is a threat with an asterisk, not a wall. The second ability is where the build-around lives: exhaust is a once-per-game gate on an activated ability, and every time you pull that lever anywhere on the board, this grows a +1/+1 counter. That ties two mechanics into one body: a punisher that discourages responsive play, and a payoff that scales off a deck stuffed with exhaust engines. The two halves pull against each other. The damage clause wants a fast finish against a defensive opponent; the counter clause wants a long game with enough activations to matter. Neither ability needs the creature to attack, which is the quiet detail: it taxes the stack while it fattens itself off your own activations.