Dust Stalker

Five power and haste for four mana is a body well above the curve, and the end-step bounce is the bill the card pays for it. The catch is conditional rather than automatic: it only returns to hand if you control no other colorless creatures when the trigger checks, so the drawback dissolves the moment a second colorless body sits beside it. That turns a hasty beater into a deckbuilding puzzle that wants company instead of a solo aggressor that punishes you for casting it, and devoid is what makes the escape hatch reachable. Every Eldrazi printed in this design space reads as colorless regardless of the mana symbols on it, so a single Eldrazi friend (or any other colorless creature) keeps this one anchored on the battlefield. The tension is the whole strategic axis. Played alone, it becomes a recurring four-mana threat you replay each turn for a steady drip of haste damage, sandbagging it as a repeatable attacker that resets out of removal range at end of turn. Played in a dedicated colorless shell, the return trigger simply stops firing and you keep a 5/3 with haste at a rate that undercuts most comparable beaters of its size. It is a creature built to reward commitment to a type, with a penalty mild enough to ignore once you build around it and steep enough to respect when you do not.