AF: I had a feeling you were going to say the runway wasn't exactly level! All the more reason to look well ahead.
Forget the bungees - 'bouncing' is an aerodynamic effect and is entirely due to excessive sink rates on touchdown (insufficient holdoff) and mainwheels touching first, allowing inertia to move the tail down and hence increase the AoA and produce another takeoff. The effect would be the same if the u/c was solid or excessively squidgy. But then I'm sure you already knew that.....