Switcheroo

Switcheroo reverses the units' current might when it resolves, but it does not exchange their base might or set either unit's might to a new value. The Swap action determines the difference between the two current values, then creates a might increase for the lower value and an equal might decrease for the higher value.^{434.1434.1.a434.1.b} Each increase or decrease lasts for Switcheroo's stated duration, this turn.^434.1.a If the units have equal might when Switcheroo resolves, the Swap has no effect.^434.1.c

No, each existing modifier is counted once as part of the unit's current might, and it continues applying normally after Switcheroo resolves.^{478.2479.4.a479.4.d} Switcheroo calculates one difference from the complete current values and creates separate increase and decrease effects; it does not remove, reapply, or replace the existing modifiers.^{434.1.a434.1.b} For example, if a unit has a base might of 2 and an active +3 bonus, its current might is 5 for the Swap calculation. After the Swap, the +3 remains one part of that unit's might rather than being added a second time.

Only the modifier that stops applying changes the unit's might.^478.4479.4.a Switcheroo's increase or decrease keeps its originally calculated amount until end of turn. The Swap creates effects with fixed amounts when it resolves, so later changes do not cause it to recalculate the difference.^{434.1.a434.1.b}

Yes, a unit can have negative might if a bonus included in Switcheroo's calculation stops applying while Switcheroo's decrease remains.^{434.1.a434.1.b478.4} Spells, abilities, and combat-damage assignment treat negative might as 0.^143.2.c Might increases and decreases instead use the actual negative value.^143.2.c.1 The unit does not die merely for having 0 or negative might. At cleanup, it is killed only if it has a non-zero amount of marked damage equal to or greater than its might.^142.4.b323.4