Tobende Kampfmaus

Der zweite Zauberspruch, den du pro Zug wirkst, kostet beim Wirken {1} weniger.
Feier — Zu Beginn des Kampfes in deinem Zug und falls zwei oder mehr bleibende Karten, die keine Länder sind, in diesem Zug unter deiner Kontrolle ins Spiel gekommen sind, erhält eine Kreatur deiner Wahl, die du kontrollierst, +1/+1 bis zum Ende des Zuges.

Souris de combat enragée

Le deuxième sort que vous lancez à chaque tour coûte {1} de moins à lancer.
Célébration — Au début du combat pendant votre tour, si au moins deux permanents non-terrain sont arrivés sur le champ de bataille sous votre contrôle ce tour-ci, une créature ciblée que vous contrôlez gagne +1/+1 jusqu'à la fin du tour.

怒り狂う戦闘ネズミ

あなたが各ターン内のあなたの２つ目の呪文を唱えるためのコストは{1}少なくなる。
祝祭 — あなたのターンの戦闘の開始時に、このターンに土地でない２つ以上のパーマネントがあなたのコントロール下で戦場に出たことがある場合、あなたがコントロールしているクリーチャー１体を対象とする。ターン終了時まで、それは＋１/＋１の修整を受ける。

狂怒战鼠

你每回合中施放的第二个咒语减少{1}来施放。
欢庆～在你回合的战斗开始时，若本回合中有两个或更多非地永久物在你的操控下进战场，则目标由你操控的生物得+1/+1直到回合结束。

Raging Battle Mouse

The second spell you cast each turn costs {1} less to cast.
Celebration — At the beginning of combat on your turn, if two or more nonland permanents entered the battlefield under your control this turn, target creature you control gets +1/+1 until end of turn.

Wilds of Eldraine Promos

Wilds of Eldraine

Celebration abilities only care if two or more nonland permanents entered the battlefield under your control in a turn. They won't get more powerful if more than two permanents entered the battlefield under your control in a turn.

Each celebration ability has a different effect.

Others are static abilities that give creatures abilities or power and toughness increases as long as two or more nonland permanents entered the battlefield under your control that turn.

Raging Battle Mouse can't reduce its own cost, even if it's the second spell you cast in a turn.

Raging Battle Mouse's cost-reduction ability can't reduce the amount of colored mana you pay for a spell. It reduces only the generic mana component of that cost.

Raging Battle Mouse's cost-reduction ability doesn't change the mana cost or mana value of any spell. It changes only the total cost you pay.

Some celebration abilities trigger at specific parts of the turn and check whether two or more nonland permanents entered the battlefield under your control already in that turn.

Spells that were cast before Raging Battle Mouse entered the battlefield count. If Raging Battle Mouse was the first spell you cast this turn, the next spell you cast this turn is your second spell.

The permanents that entered the battlefield don't need to remain on the battlefield or under your control. Celebration abilities are checking for past events, not the current game state.