Swarm Surge

The clever part is the conditional second clause: the +2/+0 lands on everything you control, but the first strike rider asks specifically for colorless creatures, which makes this an Overrun built to reward a board that has shed its color identity. Devoid is what threads that needle. By stripping its own color, the spell is itself colorless on the stack, but more to the point it lives in a stable of creatures that read as colorless regardless of the black mana that cast them, so the first-strike clause is not the dead text it looks like in a normal black deck. Pump-plus-first-strike is a familiar finishing pattern (the effect Overrun made famous trades the evasion for trample), and the structural choice here is to gate the better half behind a tribe rather than charge more mana for it. The result is a team trick that scales cleanly with how committed you are to the colorless theme: a token-flooded board of small bodies turns +2/+0 and first strike into a combat math the defender almost cannot survive, while a deck splashing it for the raw pump gets a serviceable but unremarkable team buff. That split is the whole design: one card that is a finisher in a deck built around a single creature characteristic and a fine-but-forgettable alpha-strike enabler everywhere else.