"Listen, I don't sleep. Even if I do, I only sleep during the day." his eye twitched. The insanity would be coming soon. He started chuckling insanely. "No, no, no..." he mumbled. "I'll stay here for the night." he walked over to the wall the bed thing that Serenity was sleeping in. He sat down on the floor and began mumbling things while having his head in his arms, sort of curled up. He then started, very quietly, singing. 

(( here's the song, and he sang it exactly like it sounds in the video: [youtube]zcSlcNfThUA[/youtube] ))