On the HBO drama Game of Thrones, summoning the hellfire of a dragon is as easy for Daenerys Targaryen as saying the word "dracarys." But for Pixomondo, the VFX house that created the CGI versions of Drogon, Rhaegal and Viserion for Season three of the show, making dragons appear on the small screen took considerably more effort. Not only were the three dragons meticulously computer-generated, but Pixomondo had to create the fictional beasts completely from scratch using the movements of real Komodo dragons, birds, and bats as inspiration.

"We looked at big goose animals when they are on the ground, how they play with their wings even though they're not able to fly," effects supervisor Sven Martin told WIRED. "We had great footage of bats flying very close on top of a surface, so [we could see] what would they do with their wings."

While filming, Emilia Clarke, who plays Daenerys, initially used puppet stand-ins called "stuffies" and even a tennis ball on stick to help create a sense of physical interaction. Martin says that they wanted her relationship with Drogon to seem almost maternal; "when she's stroking him, he should be a little bit like a cat." When strangers, approach, however, Drogon can turn quickly from housecat to monster, baring his teeth in a way that reminded Martin "a bit of the Alien Queen, which even for me was very threatening."

Find out more about how Pixomondo built the dragons for Game of Thrones Season three in the video above.