A strange and unusual cloud rolled in over Central Texas last night, and people took out their cell phones to capture video of it. One person even set up a Facebook fan page that already has more than 2,000 "likes".
The San Marcos Mercury has posted some impressive pictures of the cloud.
Experts said the cloud was a cumulonimbus, which forms a towering mass with a flat base at fairly low altitude and often a flat top, as in thunderstorms. It reportedly formed over Hays County and blew off to the east toward Bastrop.
Update at 12:46 pm: RepublicofAustin.com found many breathtaking images of the cloud onTwitter and Instagram. Check them out.
Earlier: Here are two more YouTube videos. The second one is a time lapse video.