Rule evolution
Rule 701.10b
Previously numbered 701.9b.
Earliest archived Rules release: 2018-04-27 · 0 wording revisions · 1 renumbering
Added701.9bDetails
To double a creature’s power, that creature gets +X/+0, where X is that creature’s power as the spell or ability that doubles its power resolves. Similarly, an effect that doubles a creature’s toughness gives it +0/+X, where X is that creature’s toughness. Doubling a creature’s power and toughness gives it +X/+Y, where X is its power and Y is its toughness.
Renumbered
701.9b→ 701.10bDetailsPreviously
7. Additional Rules
701. Keyword ActionsThen
7. Additional Rules
701. Keyword ActionsTo double a creature’s power, that creature gets +X/+0, where X is that creature’s power as the spell or ability that doubles its power resolves. Similarly, an effect that doubles a creature’s toughness gives it +0/+X, where X is that creature’s toughness. Doubling a creature’s power and toughness gives it +X/+Y, where X is its power and Y is its toughness.