Bulwark Ox

The Saddle mechanic dresses up a familiar creature-combat idea: you tap a support crew to power up a Mount before it swings, trading board width for a bigger threat on the turn you attack. What separates this Ox from its stablemates is that it doesn't want to be big itself. Saddling it feeds a counter onto a target creature, which quietly moves it out of the aggressive-Mount lane and into a counters-matters shell where the +1/+1 is a means, not an end. That reframing is what the sacrifice ability confirms: blowing up the Ox hands every countered creature you control both hexproof and indestructible for the turn, a one-shot protection package that reads as a combat trick and a wrath-insurance policy at once. The two halves lock together: the attack trigger builds the board state the sacrifice then defends, so the Ox is both the engine that distributes counters and the escape hatch that keeps them alive through a targeted removal spell or a sweeper. The Saddle cost is what keeps the loop honest, since you can only trigger the counter by committing extra bodies at sorcery speed, and the protection is a hard trade: you get it once, and only by giving up the creature generating the counters in the first place.