A player may planeswalk only during a Planechase game. Only the planar controller may planeswalk. See rule 901, “Planechase.”
July 3, 2020 · Core Set 2021
“Monstrosity N” means “If this permanent isn’t monstrous, put N +1/+1 counters on it and it becomes monstrous.”
April 27, 2018 · Dominaria
Some spells and abilities instruct players to vote for one choice from a list of options to determine some aspect of the effect of that spell or ability. To vote, each player, starting with a specified player and proceeding in turn order, chooses one of those choices.
September 30, 2016 · Kaladesh
“Bolster N” means “Choose a creature you control with the least toughness or tied for least toughness among creatures you control. Put N +1/+1 counters on that creature.”
January 23, 2015 · Fate Reforged
To manifest a card, turn it face down. It becomes a 2/2 face-down creature card with no text, no name, no subtypes, and no mana cost. Put that card onto the battlefield face down. That permanent is a manifested permanent as long as it remains face down. The effect defining its characteristics works while the card is face down and ends when it’s turned face up.