Definition of creep:
(n) :
the movement of something that creeps (like worms or snails); a relatively small gradual change, variation or deviation (from a planned value) in a measure
"stop following me, you creep!"
(v) :
to move slowly with the
abdomen close to the ground; of
plants, to grow across a surface rather than upwards
"he tried to creep past the guard without being seen."