Sleep was a spell mages once learned which would put the target to sleep for a few seconds. Initially learnt at level 8, additional ranks could be learned at the levels 20 and 40. While gaining ranks, the sleep duration would change from 20 to 30 and 40 seconds. Sleep is likely a precursor for the Polymorph spell mages got in the live version of World of Warcraft, which would transform targets into a variety of animals rather than sending them asleep.

The spell was added in Patch 0.6 and changed to Polymorph in Patch 0.8.