Summon Undead
Sorcery
You may mill three cards. Then return a creature card from your graveyard to the battlefield. (To mill a card, put the top card of your library into your graveyard.)
The air itself shuddered at the wizard's words, and from the dark beyond, her call was answered.
Dallas Williams
The List (PLST)
• #CLB-151Rulings
If you have fewer than three cards in your library, you can't choose to mill any cards this way.
(wotc • 2022-06-10)
You can return a creature card that you milled or one that was already in your graveyard.
(wotc • 2022-06-10)
You return a creature card if there is one to return, even if you chose not to mill three cards.
(wotc • 2022-06-10)
Rulings
If you have fewer than three cards in your library, you can't choose to mill any cards this way.
(wotc • 2022-06-10)
You can return a creature card that you milled or one that was already in your graveyard.
(wotc • 2022-06-10)
You return a creature card if there is one to return, even if you chose not to mill three cards.
(wotc • 2022-06-10)