Rule 123.8 · Stickers
A power and toughness sticker is a sticker that has two numbers and a slash printed on it, resembling the power and toughness of a creature card. A power and toughness sticker on a creature or on a creature or Vehicle card in a zone other than the battlefield sets that object’s power and toughness to the values printed on that sticker (see rule 613.4b). If more than one power and toughness sticker is on a creature, use timestamp order to determine which one takes precedence (see rule 613.7).
Subrules
An effect that refers to the power and/or toughness of a sticker refers only to the printed power and/or toughness values on a power and toughness sticker. It does not refer to any printed value on any other stickers.