ANAHEIM, California — If you're planning on cosplaying at BlizzCon, you'd better bring your A game. Blizzard Entertainment's annual weekend celebration of its hugely popular World of WarCraft, Diablo and StarCraft game series drew more than 20,000 of the company's biggest fans. Those who were most addicted to WarCraft dressed up in some unbelievably elaborate costumes, from the beautiful to the horrific. Photojournalist Karen Chu was on hand to capture the best cosplay of last week's big show. Above: Mistress of Pain Last year's costume contest winner "Rainyia" brought back her winning Mistress of Pain costume from the upcoming Diablo 3 as she greeted BlizzCon attendees in the lobby. And by "greeted," we mean "fueled the nightmares of."

Blood Elf Leslie Sanduval's getup tricked quite a few con-goers into thinking that she was an official Blizzard costumed rep. Her trick to perfecting the Blood Elf look? Emerald contacts, darker eyebrows and the perfect haircut. It's all about the details.

Dragon Queen Alexstrasza Mechanical engineering student Renee Gittins used her smarts and a bit of internet research to craft armor for her Dragon Queen Alexstrasza. Gittins said she didn't think her chances of winning the annual BlizzCon costume contest were that great — she was just happy to be there.

Professor Putricide and Rotface This Professor Putricide and Rotface group costume by the Van Der Ahe family was a clear fan favorite at BlizzCon this year. "I just wanted to go as something with my dad," said Christy Van Der Ahe, "and it's fun dressing up as a big, bad boss."

Emerald Dream Brenna Boznia of San Clemente, California, spent a full year on her Emerald Dream-inspired costume, connecting hundreds of individual rings and scales to fashion her talon gloves. "I'm really good with pliers now," she said.

Hogger Alliance kids, hold on to your level-10 cloth hats — it's Hogger! Aside from the funny and rather unheroic name, Hogger was the first Elite encounter for many World of WarCraft players. Bryce Masunaga of San Jose, California, delighted fellow attendees with this costume that he started designing way back in November 2009. Masunaga kept it practical with embedded side cooling fans and custom-engineered pants.

Spirit Healer Fun BlizzCon fact: You're always able to find empty tubes and jars of body paint and special makeup in the bathroom trash cans at the Anaheim Convention Center. Lindsey used up quite a bit of Na'vi blue for her Spirit Healer costume.

Fjola Lightbane As compared to previous BlizzCons, 2010 saw a lot more fans dressing up as villains and bosses. Here we see Fjola Lightbane, half of the Twin Val'kyr boss team from WarCraft's Trial of the Crusader raid, in her Nordic-inspired getup.

Protoss Hooves Hooves are in for 2010! Many Protoss, Draenei and Satyr cosplayers fashioned their own outrageous hoof shoes this year. This pair of Protoss feet were crafted by taking the stilettos off a pair of high-heeled boots and using modeling compound and cardboard armor as the base.

Terran Ghost It was an upset when this Terran Ghost from StarCraft II: Wings of Liberty did not make it into the finals during the BlizzCon's costume contest this year. With perfectly molded acrylic armor, LED lights and an exact replica of the in-game rifle, she was one of the ultimate fan favorites.