The website WoWhead went data mining through the game's latest expansion pack, Warlords of Draenor, and found an NPC named Robin the Entertainer.
The NPC was tied to the character model of a genie (seen above) that seems similar (though legally distinct) to the blue genie that Williams voiced in Disney's Aladdin.
Being a genie opens up the possibility for some shapechanging, and this is further evidenced by two other NPC character models labelled as "Robin." One is a male human, the other a female human. Fans believe they may be meant to represent two of Williams' other iconic characters, Mork and Mrs. Doubtfire.
Warlords of Draenor releases November 13.