Last Stand

432.1.a. This creates an effect that modulates that attribute by that specific amount for the duration specified by the Game Effect that instructed the player to perform this action. Example: A unit with 3 base Might and Shield 2 is in combat as a Defender. Since Shield applies, its current Might is 5. A player chooses it as the target for Last Stand, a spell that reads in part "Double a friendly unit's Might this turn." Its current Might is 5, so it gets +5 Might this turn, for a current Might of 10. After combat, Shield no longer applies, but the +5 Might from Last Stand does, so the unit's Might is 8.

477.3.c. Players cannot increase a numeric attribute by a negative amount. If an effect would instruct a player to do so, they increase it by 0 instead. Example: A player plays Last Stand, which reads "Double a friendly unit's Might this turn. Give it Temporary." The player declares a 2 [M] unit as the target during finalization. In reaction to Last Stand, an opponent plays Eclipse targeting the 2 [M] unit. When Last Stand resolves, the unit is -2 [M]. Last Stand instructs its controller to increase the unit's Might by its current amount, -2, when the double action is performed. This is not possible, so the unit's Might is increased by 0 instead.