Halo Hopper

A colorless convoke creature is the design that makes the mechanic universal. Convoke normally rewards you for playing a lot of creatures in one color, since each tapped body pays for a generic or a mana of its own color; the payoff is loudest when you can turn a monochrome board into a big swing. This 3/2 asks for none of that specificity: with a fully generic cost, every creature you tap toward it counts for one, no matter what color it is or what deck it lives in. That makes it a Frog any board can cast, a body that costs three mana in a vacuum but zero mana across three idle creatures. The catch is that it convokes into a modest 3/2 with no evasion and no text past the cost reduction, so the incentive to lean on convoke is entirely tempo: you are spending taps to deploy a creature without spending mana, freeing that mana for something else the same turn. Being an artifact creature is the wrinkle that keeps it in the conversation past the raw stats, letting it register for anything that cares about artifacts on the battlefield or colorless permanents while still swinging as a body. The design is honest about what it is: a cheap-to-convoke filler body whose only trick is being castable in any color at all.