Invasion of Ikoria
Battle - Siege
(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Ikoria enters the battlefield, search your library and/or graveyard for a non-Human creature card with mana value X or less and put it onto the battlefield. If you search your library this way, shuffle.
not legal Legacy
not legal Vintage
not legal Modern
not legal Standard
not legal Pioneer
not legal Pauper
not legal Commander
not legal Frontier