A Southwest flight bound for Burbank that took off from Oakland Airport just after 7 a.m. this morning had to turn around and land twenty minutes later after a mysterious odor filled the cabin and sickened a flight attendant.

The source of the odor still has not been determined as of this hour, but the flight attendant walked off the plane on her own and was hospitalized, and all the passengers were taken off the plane as well.

The flight had 139 people aboard. No word on whether the flight attendants used any of their signature quippy jokes to diffuse the odor situation in flight.