Dynacharge

The overload mechanic's pitch is right here: a single pump spell that scales from a one-target combat trick into a battlefield-wide attack step, with the price tag deciding which one you cast. For a lone red mana it nudges a creature +2/+0, fine if unspectacular, but pay the overload cost and that buff hits every creature you control at once, turning a stalled-out board of tokens into a lethal swing. The whole design rides on what red aggro tends to have lying around when it wants this: a wide board it can no longer profitably attack into one blocker at a time. A flat +2/+0 to a single attacker rarely breaks a stalemate; the same boost across five bodies does. That gap between the two modes is the entire engine. The reason it stays an instant rather than a sorcery matters too, since the overload version is most punishing held until after blockers are declared, when a defender has committed creatures expecting the old math. The card asks nothing in deckbuilding terms beyond the obvious requirement that you go wide enough to make the second mode worth the three-mana overload cost, which is precisely the kind of board a token or go-wide aggro shell wants to build anyway.