Unlike previous event pets, Murkalot will not be showing up in all of your characters' mailboxes because pets are account-wide. I'm not sure how Blizzard picks which character to send it to. It showed up on a level 90 I haven't played in a while, but it may have been the first character I logged into after it got mailed out.
Murkalot's idle animations include disappearing into a beam of light and then falling on the ground afterward. He picks himself up and shakes himself off before returning to his ready position.
Are you attending BlizzCon virtually or physically and have you received your Murkalot yet? What do you think of him?