The Under the Bed monster is a strangely moral creature, his job and his title are on and the rules are quite clear, it�s the 7th night under the bed that the kid is to be eaten, the nights before build up, strange noises, whispers, shadows, heavy breathing, a show of that furry paw, then appearance and if they still sleep in that bed consumption. Of course the parents only get 3 nights after there kid is eaten�.(or one night if kids) they should learn to listen. When UBM isn�t haunting a kid his behavior is much the same to the adults(Who often are institutionalized. Though theoreticly able to go after large groups at once his job generally maxes out at slumber parties or summer camps.
An odd note about hospitals, when visiting people who are in grave condtion and not �fully mature� he will do the same and eat them up but they wake up back in the hospital bed with every organ and injury fixed, apparently in a miracle.