diff --git a/server/src/objects/Deck.ts b/server/src/objects/Deck.ts
index 528439a..b905ed8 100644
--- a/server/src/objects/Deck.ts
+++ b/server/src/objects/Deck.ts
@@ -53,6 +53,9 @@ export class Deck<T> {
 	 * @param card The card to add to the discard pile
 	 */
 	public discard(card: T) {
+		if (!this._unknown.includes(card)) {
+			throw new Error("Cannot discard a card that doesn't exist in the deck");
+		};
 		this._unknown = this._unknown.filter(x => x != card);
 		this._discard.push(card);
 	};