diff --git a/src/main/java/inf112/fiasko/roborally/objects/Deck.java b/src/main/java/inf112/fiasko/roborally/objects/Deck.java
index 76a58a6..2551c6e 100644
--- a/src/main/java/inf112/fiasko/roborally/objects/Deck.java
+++ b/src/main/java/inf112/fiasko/roborally/objects/Deck.java
@@ -15,7 +15,7 @@ public abstract class Deck<T> implements IDeck<T> {
      * @param cardList list of cards
      */
     public Deck (ArrayList<T> cardList) {
-        this.cardList = cardList;
+        this.cardList = new ArrayList<>(cardList);
     }
 
     @Override