Extraterrestrials Invade California! Alien Con 2016 in Photos

The History Channel hosted a convention for fans of the TV series “Ancient Aliens” and science-fiction enthusiasts in Santa Clara, Calif. over the Halloween weekend. Check out the incredible costumes and celebrity guests in this gallery.

An Alien Con attendee takes a selfie in front of giant sculpture of a wrecked spaceship on Oct. 28.

This Alien Con attendee poses for a photo in the clutches of a vicious-looking alien.

Alien Con 2016 hosted a saber combat workshop for attendees on Oct. 29.

An inflatable alien sits behind the reception desk to greet visitors at Alien Con 2016.

Two Alien Con attendees dress up for a costume party on Oct. 28.

A vendor sells alien masks at Alien Con 2016.

Alien Con 2016 attendees takes pictures of a man in an impressive alien costume on Oct. 29.

A UFO appears to be attacking a windmill on a farm in this Alien Con attendee’s costume during the costume party on Oct. 28.

Alien Con 2016 attendees take souvenir photos at the main exhibition hall on Oct. 28.

Alien Con 2016 attendees dressed in costume at the main exhibition hall on Oct. 28.

(Left to right) Author David Childress, researcher Jason Martell, investigative mythologist William Henry, ancient literature expert Ariel Tzadok, and “Ancient Aliens” producer Max Thompson on a panel discussion during the Alien Con 2016 on Oct. 29.

Actress Katee Sackhoff of the series “Battlestar Galactica” signs autographs at Alien Con 2016 on Oct. 28.

Former child actor Bill Mumy, who played the role of Will Robinson in the 1960s CBS science-fiction television series “Lost in Space,” signs autographs at Alien Con 2016 on Oct. 28.

Actor Tom Skerritt, who played a role in the movie “Alien,” signs autographs at Alien Con 2016 on Oct. 28.

TV Producer Kristina Djokic, who worked on the History Channel show “Ancient Aliens,” speaks at Alien Con 2016 during a panel discussion on Oct. 28.

Giorgio A. Tsoukalos, executive producer of “Ancient Aliens,” signs autographs for Alien Con 2016 fans and attendees on Oct. 29.

Attendees take photos of the “Lost in Space” robot during the Alien Con 2016 on Oct. 29.

Actor Mark Goddard, who starred in the 1960s CBS television series, “Lost in Space,” signs autographs at Alien Con 2016 on Oct. 28.

This Alien Con 2016 attendee had brilliant idea for a low-budget alien costume a costume party on Oct. 28.

Star Wars’ R2-D2 also made an appearance at Alien Con 2016. Here, fans check out the robot replica in the main exhibition hall on Oct. 28.

Alien Con 2016 attendees play with Teratini VR game on Oct. 29.

Alien Con 2016 attendees purchase merchandise at the main exhibition hall on Oct. 28.

Alien Con 2016 merchandise