At the beginning of combat on your turn, equipped creature or a creature you control named Vecna gets +X/+X until end of turn, where X is the number of cards in your hand.
Equip—Pay 1 life for each card in your hand.
Equip
If you control both Vecna and Hand of Vecna equipped to another creature, you choose which creature to apply the bonus to as the triggered ability resolves.
23-07-2021
wotc
Hand of Vecna's triggered ability uses the number of cards in your hand as it resolves to determine the bonus the creature gets. It won't change if the number of cards in your hand changes later in the turn.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.