Answer: wriggler

AnswerCrossword Clue
WRIGGLERTadpole, for example
WRIGGLERMosquito's larva or pupa
wrigglerone that wriggles (to twist and turn)
wrigglerA person or thing that wriggles
wrigglerA wriggling animalcule or the larva of a mosquito