Reppy says it's possible the normal helium simply deformed as the pendulum twisted. Helium-4, which is used in the experiments, has some inherent defects that change its behavior at different temperatures, making it wobbly. Reppy says that as the temperature rises, these defects get even more wobbly, thus making helium's structure less rigid. Therefore, its changed, bendy structure at ultra-cold temperatures is not necessarily because of supersolidity. Rather, Reppy says, it's more like plastic.