alarm clock grenade 

noun. An alarm clock which is set on a short timer by someone still laying in bed and then thrown to the other side of the room. When the alarm clock goes off its user will then have no choice but to get out of bed to turn it off. A common method of waking one’s self up.

'I was having trouble getting out of bed on Monday morning, so I chucked an alarm clock grenade.'

alarm clock grenade by KartoonHead September 26, 2011