I Won't Let You Sleep Tonight
Beelzebub has been crying all night for the past three nights, which is causing Oga and the whole neighborhood to get very little sleep. Wanting to stop his night crying to avoid being chased out of their house, the Oga family attempt to play with Beelzebub all day in order to tire him out come nighttime. Despite managing to get him to sleep, Beelzebub still wakes up and cries in the middle of the night. After Oga spends the day dealing with a sleep deprived Tōhōshinki, Hilda brings a toy that calms Beelzebub down, but is even noisier than his crying.
Aired 10/04/2011EP 12 - I Won't Let You Sleep Tonight

Beelzebub
Oga Tatsumi is a first year student in Ishiyama High, a notorious school for delinquents. One day he sees a man floating by, and the man suddenly splits in half to reveal a baby boy inside!
(Source: Crunchyroll)