Drown in Filth

Oracle Text

Choose target creature. Put the top four cards of your library into your graveyard, then that creature gets -1/-1 until end of turn for each land card in your graveyard.

Card Rulings

4/15/2013 You choose the target of Drown in Filth as you cast the spell. You won’t necessarily know what will happen to that creature’s power and toughness at that time.