Favored Hoplite

Point a spell at this hoplite and two things happen at once: it grows, and it becomes untouchable for the turn. That second clause is where the design separates itself from the rest of its keyword's roster, most of which only stack a counter. The prevention rider turns every trick into a combat guarantee. Aim a pump spell at it before combat, ram it into a fatter blocker, and the blocker dies while the hoplite walks away with a counter and no scratch on it. Burn pointed at it after the trigger resolves still resolves, but the damage never lands: the removal accomplishes nothing. A chump that should trade up trades nothing at all.

The cost of all this is that you have to spend real cards feeding it. A 1/2 sitting on an empty board does nothing, and the engine only fires off your own spells, so it demands a deck stuffed with cheap cantrips and combat tricks rather than one that happens to run a few. Density is everything: each spell you aim at it buys a permanent counter plus a turn of invulnerability, so a hand full of pump effects converts directly into a creature that outsizes the board and cannot be answered in combat or by damage-based removal on the turn it counts. The prevention clause is the heart of the design: the spell that makes it bigger also makes it immune for exactly as long as the attack needs to connect.