The unnamed snake was initially seen making its escape down rue du Commandant-Charcotin in the Caudéran area, but by the time fire fighters arrived, it had sought shelter by climbing into the engine of Mario Poularas' car via the gearbox.
Mr Poularas told Sud Ouest newspaper that he was relieved not have needed his vehicle on the morning that fire fighters knocked on his door to tell him that a boa constrictor had fallen asleep inside it.
"I don't know what I would have done if I'd seen the animal in the passenger compartment," he said.
Boa constrictors are not venomous, but are still, as Sud Ouest put it, "not cool to find while changing from first".
Fire fighters took half an hour to extract the animal, during which time its owner realised it had escaped after he left the vivarium door open.
Comment: Just to clarify, these are atmospheric phenomena, not astronomical.