When some is so enthralled with their World of Warcraft session that they barely, if at all, respond to any outside stimuli; Relentlessly pursuing their virtual quests like Zombies to brains.
Jay: "Hey Sam what you wanna get into tonight, party or something?"
Sam: ..... "Need more DPS...damage dispelled!"
Jay: "Sheesh, dudes turnin WoW Zombie on me already."