インスタント
クリーチャー1体を対象とする。ターン終了時まで、それは-X/-Xの修整を受ける。Xはあなたの墓地にあるカードの枚数に等しい。
Festive Funeral is still on the stack while you determine the value of X. It doesn't contribute to the value of X.
The value of X is determined only as Festive Funeral begins to resolve. The target creature's power and toughness won't change if other cards are put into your graveyard later in the turn.