Flight Attendant reported a loud bang as they were about to take off. Takeoff was rejected and aircraft was towed back to gate after both engines were shut down.

Narrative

Right as we were about to take off I heard a very loud bang come from the left side of the aircraft. The takeoff was aborted and we pulled off the runway. The pilots came over the PA and said Remain Seated". I called the back to ask if they heard the loud bang. They did. FA A said that she saw smoke on the left side of the aircraft. I looked out 1L and 1R and did not see any smoke. One of the flight attendants went out to double check and saw that the smoke was disappearing. The captain called and asked us to check the left engine. I reported what was just told to me from FA B and told him we would double check what we saw. FA B and I both walked through the cabin and checked the left engine. We did not see any fire or smoke. I did see that the back left flaps looked charred / burned. Many passengers sitting behind the left wing told us that they saw BOTH fire and smoke when they heard the loud bang. I reported all to the captain. All three of us continued to monitor the situation outside in case of any changes. Both engines were shut down and we were safely towed to the gate where we deplaned via the jet bridge."