I've noticed how some of the artifacts refer to "dreams" and "sleep", playing a significant role in part of the story of Spiral Knights...The Recon Module in the Gauntlet and Echo Stones from the Shadow Lairs seem to highlight this. However, as an in-game status effect, Sleep had fallen out of mainstream use by the time the game went public. In fact, there were only two known enemies in the entire game capable of inflicting sleep -- one of which, I believe, can still be found (rarely) from a Monster Cage.
Kinda ironic, don't you think?
sleep was too op when it was dealt to you (no movement, no attack. no awakening when hit, only when it weares off), and too weak when it was dealt to monsters (they wake up, and while asleep they heal). perhaps a fix on how sleep works would do the trick ( one of the possible factors would be having the option of awakening sleeping comrades with a slap animation XD)