Rice Krispie treats can go bad over time, and there are several signs to look out for to determine if they are no longer safe to eat: Appearance: If the treats have turned hard or dry, or if they appear discolored or moldy, they have likely gone bad and should not be eaten. Texture: Rice Krispie treats that have become hard, tough, or chewy may have gone bad. Smell: If the treats have a strange or off-putting odor, this is a clear indication that they have gone bad and should be discarded. Taste: If the treats have a stale or rancid flavor, this is a sign that they have gone bad and should not be eaten. It's always best to err on the side of caution when it comes to consuming food that may have gone bad. If you are unsure if your Rice Krispie treats are still safe to eat, it's best to discard them and make a fresh batch.