diff --git a/src/main/java/inf112/fiasko/roborally/objects/RoboRallyGame.java b/src/main/java/inf112/fiasko/roborally/objects/RoboRallyGame.java
index 54ea4f6..f56c624 100644
--- a/src/main/java/inf112/fiasko/roborally/objects/RoboRallyGame.java
+++ b/src/main/java/inf112/fiasko/roborally/objects/RoboRallyGame.java
@@ -165,6 +165,8 @@ public class RoboRallyGame implements IDrawableGame {
             case BACK_UP:
                 gameBoard.reverseRobot(robotID);
                 break;
+            default:
+                throw new IllegalArgumentException("Not a recognized action.");
         }
     }