Flash
You may have Activated Sleeper enter as a copy of any creature card in a graveyard that was put there from the battlefield this turn, except it’s a Phyrexian in addition to its other types.
You don't have to choose a card to copy. If you don't, Activated Sleeper enters the battlefield as a 0/0 creature and is probably put into your graveyard immediately, unless something is increasing its toughness to keep it alive.
09-09-2022
wotc
If the chosen creature card has {X} in its mana cost, X is considered to be zero.
09-09-2022
wotc
Treat Activated Sleeper as though it were the chosen card entering the battlefield, except it's also a Phyrexian. Any "As [this creature] enters the battlefield," "[This creature] enters the battlefield with," and "When [this creature] enters the battlefield" abilities of the chosen card will work.
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.